You can levy plenty of criticism at finance. But they certainly take smart kids from wherever they can get them (for certain jobs; for others you need certain polish).
Personally know of 1 from Ghana and 1 from Nigeria - both engineers in HFT - both emigrated to the US post-college - so not that rare. Is it proportional to population? Of course not. Clearly there's going to be an english-speaking bias and an education availability bias and whatever bias du jour one wants to bake in. I don't think it is controversial to say that being born into poverty hurts - as naively as just accounting for malnutrition, for example, and going from there...
idk to me bottom 20% is a household thing more so than geographic if you live in Ghana or Nigeria but grew up driving a Maybach or BMW that would't apply if you grew up homeless in the US it would
perhaps ancedotal but the bottom 20% more or less stay the same across generations no matter how welcoming an organization is or no matter if an individual is bright or
has a good idea