Why do you think football and basketball are not dominated by the middle and upper cl?

Especially with the modern day athletic opportunities that the upper/middle cl has. AAU Ball, money from their families to play/train competitively year round, access to superior gyms and workout facilities, safe neighborhoods with no lure of gang life. With all the inherited advantages these kids have, there is no question that the premier athletes should be coming from the upper social cles, on paper. How are these two sports still dominated at the collegiate and professional levels by people who have come from the "bottom" social cl?