- the wealthiest/most financially supportive parents/relatives
- upbringings that are conducive to academic success
- the most free time
as those are the ones who, by a large margin, attend top schools, work at top companies, and have time to spend on self-learning. Another data point of confirmation of a well-studied idea.
Assortative mating: http://www.economist.com/news/briefing/21640316-children-ric...
Few poor at rich schools even all these years later: https://www.nytimes.com/2014/08/26/education/despite-promise...
Why people care about elite schools: https://medium.com/@spencer_th0mas/why-america-cares-about-e...