I won't get into detail but this is not true at all.

The US is a buyer market for labor. If you get ahead through hard work you just kick someone else down the ranking.

Given a seller market for labor capitalism can absorb an infite amount of poor, lazy, dumb, bad decision making, slacking people and pay them good wages in the process. The stronger the seller market the easier it is to exploit people upwards the economic ladder.

Considering the paradox of competition it is entirely possible that once every person is making "good financial decisions" everyone is worse off in the end.

Poor people indeed often make bad decisions (not necessary financial, but like taking college degree they don't need or staying with their parents until they are 40).

But realistically it's much easier to save money when your income is $10K per months vs when your income is $1K per month.

The UK did a great thing recently: there's semi-mandatory private pension contributions: it is 8% total (you can opt-out, but you need to explicitly do that). So even folks making poor financial discussion will own some wealth.

AFAIK in the US there's no minimum contribution to 401k.