I see enough and know a few relatively "rich" people that go against American capitalism. They're obviously not Musk and Gates, but where they have no wants and would be able to weather most any hardship thrown their way, short of the catastrophic medical emergency (but again, that is only a function of American capitalism).

It's hard to point at a specific part of the American system and say "this is what is wrong". I think a lot of millennials are coming to the conclusion that the system is broken and is absolutely stacked against them. Student loans, medical debt, the housing market, stagnating wages amongst record profits across the board, bailouts for banks, Wall St corruption, billionaires paying $50 in taxes, continued failed DoD audits and lost money. There is plenty of money in the system to be "given away" when the receiving party is a corporation or hedge fund or defense contractor or bank.

It also doesn't help that anyone not retiring in the next 20 years is paying into Social Security under the assumption that it's lost money. The devil that is socialist programs is a hard sell when the population blaming you for the "collapse of American Capitalism" actively benefits from a program I'm paying into, but will likely never see benefit from. Universal Healthcare UBI, free school lunches etc seems way more palatable through that lens.