In retrospect the big dividing line is kids from cultures that value education and long term thinking and ones that don’t.
In the former category, the Asian and Eastern European Jewish parents took their little income and understanding of the system to make sure their kids studied their assess off, saved for emergency and eventual investment, etc. consequentially many of those kids are now in the 1% or close.
Kids from countries with less focus on education didn’t do this with regularity and their kids are by and large nowhere near the top today.
Despite in the early 1990s being on an identical starting line. I mention this because high empathy leads us to assume that poverty locks people into bad choices. The Asian parent example shows the opposite - the poorer you are the more your choices really matter - you only have a few dollars and a few hours and how you spend them really matters.
Obviously what I wrote also depends on the degree of opportunity that exists around you. The US is still a place where you can expect to alter your trajectory if you single-mindedly focus on it. The real challenge is how to give that focus to begin with. Eg immigrants from Asia etc came here with that value system and drive already and this achieved amazing outcomes. If you don’t have that culture and drive, how do you bootstrap it? I don’t have the answer.