I’d make an even broader generalization, which is that all of these attributes are proxies for status. Graduated from a top school? Live in the Bay Area or NYC? Did well in High School (I guess?) These are all status indicators in the mind of someone higher up, and deserving of better pay. If you live in a low cost of living area it’s correspondingly lower status and deserving of lower pay. Other common status indicators include things like age, gender, and race…

Is it possible that people who are good at acquiring status markers are also good at other things? No, it’s the world that’s wrong - there is no reason a Harvard grad in NYC should have a higher chance of being paid six figures than a University of Missouri-Kansas City grad in Missouri.