alt Hacker NewsWe don't embody it, not by a long shot. We're old now.
I'm speaking about 20 years ago, when getting any kind of peer or social circle respect had the prerequisite of subscribing to socialist utopian ideals, and it wasn't something that was hard to foster in America's dead-end job work culture (which is where you work when you are young). This is urban/suburban America, where most people live.
From what I can tell this was the same with Boomers (they were the OG hippies afterall) and I see the same ideas in today's crop of young people.
The youth however hold little sway over the direction of the country, they're not actually that invested, so by the time they are having an impact, many have already received their first shots of the euphoric side of American capitalism, a career that gives them power and money (after years of wading through dead-end/entry level hell).
My point is that they didn't meaningfully embody collectivism even when they were younger. Collectivism is rice farming culture. https://www.sciencedirect.com/science/article/abs/pii/S00142.... You work together within a rigid social structure and share communally in the proceeds. But you have to precisely follow your socially prescribed roles because that system only works when everyone does what they're supposed to be doing. This is true even in developed countries that are more collectivist. Subordination of the individual to the collective is a big deal in Japan and Scandinavia. In both places, it's taboo to stand out in the crowd: https://en.wikipedia.org/wiki/Law_of_Jante. Individualism is necessarily in tension with collectivism and socialism. Individualism promotes status competition, and when status competition exists, communal sharing in the proceeds of collective labor becomes impossible.
American millennials were hyper-individualistic and rejected socially prescribed roles even when they were young. What they wanted wasn't collectivism, it was a higher status within capitalism. Which is why, as you observed, the sentiment evaporated once they achieved that status. I'd make the same point about Gen Z. They want to think they're socialist and collectivist. But they all want to be online content creators and influencers--jobs that only exist in hyper-consumerist, capitalist societies!
This is not a criticism either of collectivism or millennials, by the way. I think Republicans screwed up the concepts during the Cold War era by successfully labeling Democrats as collectivist. What you have in the U.S. is more accurately described as two strains of libertarianism, one that emphasizes social liberty and the other that emphasizes economic liberty.