Excuse my pet-peeve rant, but the "random personal contacts" line is characteristically vague. In some sort of reflexive pursuit to avoid admitting irrational f

Excuse my pet-peeve rant, but the "random personal contacts" line is characteristically vague. In some sort of reflexive pursuit to avoid admitting irrational factors, explanations become necessarily vague. For example, the irrational factors could be nepotism (which is certainly the case if being in certain location is vital), social status (it's not as cool to both start and fund/invest in a business in some unknown place), public relations ("It's the new hot tech from SV looking for an IPO in 3 years!") and so on. But then, like magic, everything is translated into vagueness: "It's because everything happens here!", and to add insult to injury there's some overall idea that the whole thing is meritocratic.