Comment by fastball

Yes, that is what OP is saying, I'm just not very convinced. Primarily because his sample size is quite small – he says the people in his smaller, non-SV jobs were just as competent as those in the SV company, but that could mean a number of things that are not "SV isn't meritocratic". For example, it could just be that his previous colleagues were more competent than the actual national/global average, which seems probable.