We can do a random search through the founders of various unicorns. My first hit was Brian Chesky [1], one of the Airbnb founders. His parents were social workers. Stripe was founded by two brothers who were born in Limerick, Ireland. Maybe they were middle class in Limerick, but most likely not rich by global standards. They are now worth $3BN each [2]. Instacart was founded by Apoorva Mehta, who was born in India, and whose parents immigrated to Canada in 2000. Apoorva doesn't have a wikipedia page, but again, very likely his family was not rich.

If you go through the wikipedia unicorn list [3], you'll find many founders that appear to be from middle or upper-middle class, but also many founders from lower-middle class as well.

[1] https://en.wikipedia.org/wiki/Brian_Chesky

[2] https://en.wikipedia.org/wiki/John_Collison

[3] https://en.wikipedia.org/wiki/List_of_unicorn_startup_compan...

Like, I appreciate your investigations, but none of those people were mentioned in the original post to which I responded.

Mark Zuckerberg: father was a dentist; solidly upper-middle class Bill Gates: mother on the board of IBM, upper-middle class

I won't try to talk about anyone except the Collison brothers, and given that I was born somewhat before them in the same country, I can assure you that they were solidly upper-middle class by Irish standards. Also, please note that Patrick Collison attended MIT as an international student, which is not something that poor people do.