Getting into a very top US university has big consequences: "attending an Ivy-Plus college instead of the average highly selective public flagship institution increases students’ chances of reaching the top 1% of the earnings distribution by 60%"

https://www.nber.org/papers/w31492

Diversifying Society’s Leaders? The Determinants and Causal Effects of Admission to Highly Selective Private Colleges

Founded in 1920, the NBER is a private, non-profit, non-partisan organization dedicated to conducting economic research and to disseminating research findings among academics, public policy makers, and business professionals.

NBER

Given that, we'd better hope it's a really fair admissions process, right? Nope!

"Children from families in the top 1% are more than twice as likely to attend an Ivy-Plus college as those from middle-class families with comparable SAT/ACT scores."

"Two-thirds of this gap is due to higher admissions rates for students with comparable test scores from high-income families".

Those differences right at the top? Driven by (among other things) preferences to children of alumni. To someone not in the US, that's just insane.