One reason may be that UCLA/USC/Stan and the deep south teams almost never
play competitive indoor tennis, except for this event. Indoor courts are faster than hard outdoor courts, so traditional indoor teams like the 4 in the semis have an inherent advantage. needless to say you still have to have the players. I am not sure why Stanford men's tennis has fallen so far. They did not even make the NTI field and have won more NCAA titles than anyone.