What's interesting is that there are places where people are paid much less because there's so little demand for labor there- if you're the only employer of software developers in 100 miles, you can pay a pittance. And at the same time, places like Silicon Valley pay a premium for labor because there's a shortage (let's not discuss the reasons around that- I don't feel the need to drink).
When the market is merged, it will be leveled. And I cannot imagine those who stay in San Francisco are going to benefit. But the brilliant developer who has been paid terribly at a small software firm in the middle of no where, who can't leave for other reasons, that developer is going to see their fortune changed for the better.