I moved from Bumblefuck, Florida to the Bay Area and, while my salary increased by about 40%, my cost of living tripled, so I'm doing far worse than I was back in B.F.

I stay mainly because of the number of tech companies in the area. Anyone can lose their job at any minute, and if/when that happens I'd rather be in an area where there were options across the street than in an area with one option two towns over. I'd move back in a heartbeat if there were a more robust tech hiring market in the boonies.