I'm not sure exactly how you'd back something like that up with data.

I also don't think the broader point is arguable. Millenials were all young adults or teenagers during the Great Recession, which is not the case for any other generations. In the same way, any other loosely defined generation will have experienced certain things at a different stage of life than other generations experienced the same events.

Just because there's no perfect way to draw certain distinctions, doesn't mean you can't capture something useful with imperfect distinctions. Of course, it's possible "generations" aren't a useful idea.