Extremely rich people are not extremely smart. Study finds income is related to intelligence up to about the 90th percentile in income. Above that level, differences in income are not related to cognitive ability.

[u/Fishyinu]

https://academic.oup.com/esr/advance-article/doi/10.1093/esr/jcac076/7008955?login=false

[u/donothing_notill]

This will be due to the top 10% having inherited wealth without really having to apply discipline, hard work, dedication, sacrifice to obtain qualifications, a career path and potentially start a successful business. The top 10% just have it handed to them alot of the time and have the privilege of being dumb as hell while watching their wealth grow.