[microcolonel]

I will say that a lot of this is self-reinforcing: huge SFO/SEA companies offer competitive compensation, so the majority of people who have competitive compensation live where they are offered, and this sends a signal to yet more people that that's where the competitive compensation is at.

If you generated that much perceived value in Manchester, NH or Topeka, KS then you could probably manage to have cash flow like that without being in SFO/SEA. Yes, a lot of that value exists only because these people can see eachother in coffee shops and meetups, day in and day out, year round, in the same place; but once you're in, being in SFO or SEA is not why you're worth paying that much.