It's the same human fecal matter. In the aggregate it is what it is -- how it reacted to a situation is how it will react.
Unless you are saying take Millenials and Boomers and switch places *when each person hits 21*. Then yes, the situation will be different. But who cares? It won't be anything to do with them. It will just be because the extruded plastic machines of their youth formed them into a different shape.
But the fact that people are proud (or ashamed) of their cohort is ridiculous. They had no agency in who they became, in the aggregate.
Individuals differ, yes, of course. But groupings like this are just another way for people to say HURRAY FOR MY TEAM!
Which is just a way to say HURRAY FOR ME!