Generation Why?

Andrew Sprung hates indictments of entire generations:

Generations are the ultimate granfalloon, Kurt Vonnegut's term for an illusory community. Babies are born every second.  A baby born in 1945, just outside the traditional boomer ring-fence of 1946-1964, would have a lot more collective experience in common with someone born in 1946 than that '46er would have with someone born in 1963.

I'll grant that those living through epochal events like the Depression and World War II may be likely to share some very broad psychological imprints not shared by those who didn't live through them. But any age brackets placed around those alleged to have been shaped by those events must be so approximate as to border on arbitrary. And of course, the imprint of those events is as varied as human circumstance and personality. In any case, given the seamless continuum of birth, and the full age spectrum of responsible adult actors (say, 18-85) at any given decision point, the boundary at which one "generation" hands off responsibility to another is a mirage.