Because the Great Imperial Powers who began and fought WWII had done so under the mantra that "bigger is better", they were hardly shaken by the emergence (near the war's end) of the A-Bomb and the V-2, surely two of the biggest, most expensive and complex weapons systems ever built up to then.
For the emergence of these style of weapons merely supported their post-1945 expectations of eternal dominance over other smaller nations and over their own colonies and subservient satellites.
With 20/20 hindsight, they should have been much more worried about other much smaller, much cheaper, much simpler weapons that emerged out of WWII : like the bazooka , above all.
Before discussing this counter-intuitive supposition, let us briefly mention some other "weapons" that surfaced during WWII.
Weapons like the art of successful low-tech microfilming, the development of inflatable rubber boats and of reliable parachutes, and the arrival of long distance radio transmitters of very small (concealable) sizes.
These all sound more like the art of spies and they are.
All that and more, much more.
Spies, Saboteurs,Resistance, Fifth Columnists,Quislings, Partisans, Guerrillas, National Liberation Armies, Commandos, Coast Watchers, Assassins, Double Agents, Governments-In-Exile.
All words we grew to hear often in WWII, most of them creations encouraged (fools !) by the Great Imperial Powers.
And a concept much in use during WWII, but not described in these terms : Technicals.
(The word means the use of essential hence widely available civilian technology to wage military combat --- such as using civilian trucks and cars to mount heavy infantry weapons.)
But it should also include, for example, the use of cell phones to set off remote bombs, the use of common diesel fuel and farm fertilizer to make those bombs and much more besides.
For its use in WWII, I am thinking about our normally incredibly complex civilian telephone systems.
So in places like the Netherlands they were successfully used, right under the noses of the bewildered Germans, by the Resistance.
The miniaturization of civilian (and sometimes military) technology, promoted mostly by the Great Imperial Powers, came back to bite them in the rear during and after WWII.
Asymmetrical warfare has actually been around forever but had almost always been a top-down affair, with bigger imperial powers easily beating smaller colonial forces.
In the air and on the High Seas, the top still basically dominates the bottom.
But unlike birds and fishes, none of us humans actually lives in the air or on the High Seas.
On land, asymmetrical warfare now swings both ways and the smaller forces can often best - in the long run - a bigger more sophisticated force intent on occupying their land.
There are many reasons why but they all come down to the fact that the ordinary foot soldier - dismissed by all sides in 1940 in favour of the mechanized army - is back and he/she is as small, mobile and elusive as ever but is now armed to destroy the big and the mechanical.
WWII saw the development of 'heavy' machine guns that weren't actually that heavy or expensive or required large crews to move and operate but actually kicked an even bigger punch, despite all that.
The infamous MG 42 of Germany being the parent of them all.
The Stokes mortar, (today best know in the 81 mm mortar version) was invented in WWI by an complete amateur and eventually replaced a 1000 years of very heavy ,very useless mortars.
It gave the infantry an extremely lethal artillery piece that was well suited for untrained soldiers and infantry fighting conditions and was cheap and light enough to carry around by a crew of three.
(Or less - the smallest 50 mm size - the forerunner of today's shotgun style grenade launcher, was easily carried about and operated by one person).
Improved optics, together with better bullets and propellant powders has made the bolt action/ single shot anti-personnel and anti-material rifle, together with the sniper pair operating it, about the best return on investment of any weapon known.
Nothing can appear to be more simple and crude and yet more effective.
But none of this cut any ice in 1940-1941 , not after the world's best military minds digested the response of the best regular (professional) infantry forces in the world to the tiny Panzer I and Japanese Ha-Go 95s, both regarded (even then) as light (ie small) tanks, yet the actual tanks that won the Blitzkrieg and the Japanese's early shock triumphs in places like Malaysia.
Put simply, over and over again the regular infantry panicked and ran at the mere sight of these tiny tanks (about the weight of a pick up truck and some not even as tall as an ordinary man) , with their ordinary machine gun as main gun and half inch cheap steel armour for protection.
If the infantry had had even the American Browning .50 cal machine guns, their half inch bullets would have torn through both tanks, but the infantry did not.
Like the Stokes mortar, the Browning 50 cal is about 100 years old in design and still the frontline weapon of choice in its class.
By the by , this type of situation common in infantry cum asymmetrical warfare, is unheard of in all other parts of military weaponry : proof that in this type of warfare, public domain designs and low tech weapons can still rule the day.
The awkward to use and move heavy anti-tank rifles of 1940 (the British Boys rifle is typical of all of them) could penetrate a light tank hull, if lucky, but generally couldn't do so fast enough to stop a major attack by more than a small handful of tanks .
Let's switch to 1944-1945.
Now even amateur infantry (like the young teenagers and elderly men of the German volk troops) were unlikely to bolt on the sight of masses of Tiger II tanks, or Russian IS-2 tanks, advancing towards them, if they were occupying infantry-friendly ground.
Yet these 70 year old tank designs remain formidable main battle tanks even today, still un-defeatable except by the very newest main tanks designs.
So what gives : why should professional soldiers run from tiny toy tanks, while amateur troops boldly faced top quality main battle tanks undaunted ?
The difference was the development of the Bazooka and its ilk, the forerunner of all of today's rocket propelled grenades (RPGs).
That and the discovering that tanks are best fought by infantry in locations where the terrain greatly favours infantry and hurts tanks.
Ultimately these deadly RPG tank killers ( killers at least in infantry friendly places) can be as short as two foot long and very light (five pound), easily carried on the back of even a child soldier, quickly put to the shoulder, fired once and the launcher tube thrown away.
In 1940, the thin, cheap armour on the Panzer I tanks could be defeated, usually, by a 25 pound Boys style anti-tank rifle but to do so the Boys needed an inordinately long heavy barrel and packed a terrific recoil, all to successfully fire a tiny but very fast and very dense bullet.
But as tank armour went up and up in thickness and in improved shape and strength, it took a very big dense shell, together with a very long gun ( ie very heavy) barrel and a very large sturdy (ie very heavy) gun carriage to destroy it before the tank destroyed (or simply outran) the now effectively immobile anti-tank gun and crew.
Right to the end of the war and beyond, a top of the line anti-tank gun like the German 88mm or the British 17 pounder, in an entrenched (out of sight) position could destroy the world's best tanks coming side-on to it , in broad daylight and in an an open field.
Ie it could destroy tanks in the typical conditions found in a military proving grounds.
Oh, you wanna talk about real world war conditions ?
Not so good.
By 1943, a successful anti tank gun was way too big and way too heavy to hide or move about quickly. It was easy to see and hit and it couldn't handle being outflanked by fast moving tank columns.
Tank success meant breaking through and past dug-in anti-tank positions, not engaging them one to one.
But using the technology of very fast, very dense small shells to fly very quickly and accurately to a (rapidly moving) target a mile away with still enough energy left to punch its way through seven to ten inches of excellent armour is still the best way to destroy tanks in open field combat.
But to do so and survive, you need to take the anti-tank gun out of its gun carriage and to fit into a tank ( ie the combo becomes a tank) because only a big ,well armoured, fast main battle tank can take on other main battle tanks in open field combat without being out-manoevered.
But tank to tank fighting is not a slugfest, because the first shot to hit a tank is usually enough to destroy it and its crew : so a bigger, longer gun can destroy a tank from further away , which is the effective real world equivalent of hitting it first before it hits you.
Ever bigger anti tank guns, ever better anti-gun tank armour : main battle tank development never stops, with most tanks out of date by the time they go into production, so the cycle starts over again.
It is deadly serious, expensive, sophisticated game that only a very few Great Imperial Powers can play.
But in urban areas, in jungles, forests, mountains, hills and rivers, in soft mud or sand and in deep snow (ie in infantry friendly areas) , masses of rapidly advancing tanks must slow to a crawl and proceed single file.
Now small,light,cheap, low tech, close-up ,hand-held, anti-tank weapons of the infantry can destroy these tanks --- or at least hobble their tracks and render them immobile and then destroy them on the second or third shot.
The secret of this amazingly asymmetrical combat success was actually known for about 65 years before it was first put to work in the famous bazooka.
So the best method to destroy armoured vehicles was actually known well before the first tank was even invented and well before the Blitzkrieg.
If this weapon had been in common use in the 1930s, there might have been no quick tank-led victories for Hitler and WWII might have ended almost before it began - and 70 million lives saved.
The effect is called the Munroe Effect or shaped charge or hollow charge.
Like most science, it was discovered by accident.
If an explosive charge is shaped to implode inwards (ironically
somewhat the way nuclear weapons work) into a hollow cone shaped void it is more effective -- this was known even in the 18th century.
Munroe happened to line that cone shaped void with a thin metal liner which, it was discovered, did some very interesting things once it moved into the void pushed by the explosives behind it.
Now all the normally dispersed ( in a 360 degree sphere) energy of an explosion is highly concentrated into a thin linear jet of plasma - the liner had become a white hot bullet of molten metal moving right into whatever was straight ahead.
The plasma does not melt its way through the armour - but it is moving so fast, it is breaking through the armour just as the anti-tank shell does - by sheer bull force concentrated on a very near front.
So who cares, one might ask ? The tank is destroyed equally well by a dense small solid bullet or a small light liquid bullet.
One cares, because the first bullet needs a very large and very heavy gun to use low energy propellant powder to send a high speed bullet one mile to destroy a tank.
By contrast, the Munroe bullet can consist of a three pound hand grenade which can be tenderly laid on the tank armour by an eight year old kid : the explosive acts as an ultra high speed anti-tank gun, albeit over the distance of mere inches!
Attaching such a grenade (using an adhesive or by magnets) did occasionally work, even in real combat in WWII, but it was really a suicide mission to get that close to a tank.
(The actual explosion wasn't necessarily dangerous.)
What was needed as some way to gently propel that three pound grenade towards the tank from a more practical infantry survival distance.
Gently because force wasn't need for this anti-tank weapon to be effective and because force came at far too heavy price : it meant a big (visible) heavy (immobile) artillery piece like the German 88mm that ultimately was only safe from itself being destroyed when encased in a big mobile, heavily armoured vehicle called "a tank".
Now a rocket, recoilless rifle or a special kind of spigot mortar can easily and gently (slowly) propel a three pound grenade more than a half kilometre away without being too big (not exactly hand-held size but still under a fifty pound size for the launcher).
However to save size and weight, the propulsion method must be gentle and the grenade travels slowly.
(Roughly 30 meters a second for the slowest Panzerfaust models versus roughly 1000 meters a second for the gun style 88 mm type anti-tank weapons .)
Even with a relatively slow moving tank (remember the infantry is best at destroying tanks when they have slowed to a single file crawl), the slow moving grenade is still likely to miss the target aimed at, by the time it arrives 600 metres away.
(Neither the infantry soldier-aimer nor the rocket itself are very accurate in any case.)
So while a conventional anti-tank gun is highly accurate out to one thousand metres, the time its shell travels in one second , the slowest anti tank grenade moving only 30 metres a second is highly accurate out to 30 metres, the distance it travels in one second.)
But at distances of say 100 metres, there is a nice balance between increased survivability for the infantry soldier, a smaller, lighter,cheaper grenade and launcher, and insufficient time between firing and hitting to make the aim inaccurate.
They can be incredibly low tech : WWII versions were made of wood and tin plate for launcher and used black powder for propellant : they have been successfully made by avid amateurs in small machine shops.
And by the world's biggest powers too , the best known one is still made of wood, tin plate and black powder.
The cheap, reliable, hand-held RPG 7 has been used all over the world by terrorists and national liberation forces : it still can destroy tanks, bunkers, helicopters and aircraft taking off or landing and wreck the command and control of warships if they hit the bridge.
A single untrained soldier with a cheap RPG 7 is not the easiest target for the high tech weapons to hit : too small, too mobile, too easily blended back into the civilian population.
And in any case, hit the soldier and RPG and many more are still left to fight on.
This combo of foot soldier and RPG has become the biggest single reason why Great Imperial Powers can no longer be sure they can push their weight around in other people's countries.
One best sees this by looking at the most published WWII photos of cities being occupied or re-captured or liberated.
The incoming victorious column is always, always, led by a long line of tanks covered in troops.
The tanks make a thunderous mechanical, unearthly roar, cowing the watching civilian population, but are really merely there to provide a photo op for people not in the actual city.
If the city was actually being defended no one would send in a long line of closely spaced tanks into its main street : the defending forces would quickly hit the first and last tank and leisurely destroy all the rest trapped in between.
Photographs of mechanical tanks cowing humans in cities became essential mental eye candy for propagandists to convey the idea that the small are inevitably helpless before the steeled might of the Big.
The real truth is that it was tanks that lost WWII, not won it, and lost it in the big city streets of place like Stalingrad.
Truer , more accurate pictures would show burnt out tanks in wrecked city streets if they wanted to tell us what really happened over the course of WWII and the Big began falling before the small....