From 1873 to 1893 to 1913, people in North America went through first the 20 years of the long depression and then the 20 years of the long boom (in Canada much better known as the Wheat or Rail Boom).
Children born early in the Era of High Modernity , say between 1870 and 1885, were old enough to fully enjoy the fruits of that long Edwardian summer of optimism and exuberance between 1893-1913.
And then were often too old to enjoy the mud (and death) of the Great War.
Those born after 1885 and on until 1900 felt cheated - they had missed the boom Edwardian Years but got to enjoy all of the mud and all of the death of WWI.
The Twenties slumped except for a brief recovery in 1924-1929, then they had the Great Depression (The Ten Years Lost/LES DIX ANS PERDU) and the tight years of WWII.
When the 20th century's long boom between 1950 to 1970 began, they were more than ready for it.
In Canada, these now-elderly teenagers of the Edwardian Era were determined to relive their missed youth - this time right - and the Canadian Natural Resources Boom of the 1950s (what I call LES DIX ANS TROUVE/THE TEN YEARS FOUND) was wallowed liberally in late Edwardian hubris .
Seen in this light of feeling long cheated, the Boom's promotors (BC premier Wacky Bennett a clear example) felt they had good cause to be free of any restraints upon their soon-to-be-fading powers.
A cohort or generation is as important as to where and why it divides internally, as for what unites these 30 years worth of children from the generations before and after them...