It links to this article with a graph showing that Brazil and South Africa have some of the worst income mobility in the world: https://www.businessinsider.com/countries-where-intergenerat...

I live in Colombia and was in Brazil recently. They're both amazing countries with great people. Go to a comuna or favela and you'll quickly see that it's incredibly difficult for lower income people in these countries to climb into a different social class.

Well, that'd probably explain South Africa - the end of apartheid there has done wonders for the number of black South Africans in better-off jobs, even if it hasn't done all that much good for overall inequality or the economy as a whole, and I suspect this one-off event has messed with however they're measuring social mobility.