I think top schools like Harvard, Stanford, Oxford etc. can serve as excellent environments for people to reach their full potential, but due to cultural reason

I think top schools like Harvard, Stanford, Oxford etc. can serve as excellent environments for people to reach their full potential, but due to cultural reasons and funding, they are willing to make large compromises on who can get a degree there. Going to Harvard doesn't mean you are intelligent, but I've seldomly seen such high density of super clever people as at these top schools.