You're going to need to define what you mean by class. It's an exceptional amorphous term and I don't see your perspective here. You will find people from countless "class" backgrounds at top schools, and even in industry there's a wealth of actual diversity on this front. For instance Tim Cook, the progeny of a shipyard worker, graduated from the prestigious Robertsdale High School [1] whose Wiki leaves me with few nuggets of knowledge about the school other than "During a school football pep rally for the Robertsdale Golden Bears to go against the Spanish Fort Toros, students were seen holding Trump flags and a sign that read 'Put the panic back in Hispanic.'" Even at places like Goldman, Lloyd Blankfein [2] is the former CEO and still the senior chairman at Goldman. He grew up in the projects in NYC. Daddy was a postal worker, mommy a receptionist.

The only common denominator you find in these individuals is being the academic equivalent of our school of 6'6" types.

[1] - https://en.wikipedia.org/wiki/Tim_Cook

[2] - https://en.wikipedia.org/wiki/Lloyd_Blankfein