Boomers in the 80s and 90s were fucking depressed. They described their lives as a boring, soul-crushing existence where they did the same hollow shit day in and day out. They hated their bosses, they hated their jobs, their kids, their wife/husband. People had "Mid-life crises" where they tried to fill the void with "a fast car and a young hot fling." things capitalism told them would make them happy. It didn't.
Seriously listen to any media made by boomers when they were in their 30s-50s. It's all jokes about how fucking mundane life is.
Even at its peak, life under capitalism was hollow and soul crushing.
They were basically taught "as long as you keep your head down and play the game, we won't hurt you financially"
Sure, (if you were white and male) you had money, but it took everything else away. Community, friendship, family. Trapped them in a gilded cage. Having to watch their children having even that promise of financial stability ripped from them. And don't get me started on how terrible it was if you weren't a white dude.
I have to wonder if the "selfish, childish boomer" stereotype is something of a coping mechanism. Maybe some boomers are like that because thats their jokerfication.
It's only something that happens in the kind of society we live in. I'm not going to say just capitalism, but societies of control generally. You're out of assigned goals, and you've only got things to lose from there on out. You have kids, job with some accomplishment, spouse, house, and are well past education. Now you'll just get physically weaker and eventually die, with your friends fading away and kids moving out to do the same shit you did. It only works if you have a society where there are very clearly set expectations, which are only designed to fulfill two things: produce money and future workers. This is mainly a problem of capitalism, but it could emerge from other systems of production.