not every Western country was on the same side of WW2, and not all of them had the fighting happen in their territory, which means not all of them were levelled. And not all of them were Marshall planned after.
This isn’t actually relevant to my point. They didn’t have the same experience as other Boomers (or whichever generation) in other countries, but did have a notably different experience from Xers (or whatever) in their own country. Because it may not have been in identical ways, but yes, every western country was affected by WWII in some ways. Even those like my own that never saw conflict at home. So the experience of being born in the immediate aftermath of the war is a handy generation-defining experience, even if what that experience translates into is different for a German compared to a Brit, or to an Australian.
Of course, it’s also fair to say that there’s a much bigger difference between a German born in 1946 and one born in 1963 than there is between two Germans born in 1963 and 1965, even though one case has two “boomers” and the other a boomer and gen X. And in either case, the experience of someone in West Berlin is probably extremely different from someone from Hamburg, from someone born in the small town of Deesdorf. And for someone born to wealthy parents or poor. Generations help categorise, and the rough boundaries we use are roughly useful, but that’s a lot of rough.
My point was that the dates can stay the same regardless of where you go, even if the stereotypes change.
What it seems like you were saying is that the dates themselves become irrelevant if you leave America. If that’s not what you meant, your comment lacked clarity.