nothing about that is surprising and is exactly what you would expect when people move to places with more efficient talent markets, especially from pseudo-feudal societies that still existed in lots of the developing world in the 20th century, and that's before you get into the selection effect.

my dad was basically expected to work the farms his entire life and school ended at the 3rd grade where he grew up, he moved to the US and became a chess master & went to one of the best colleges in the country. impossible where he was from and really shows how stupid and zero-sum-minded old world elites are compared to the US/anglo culture.