Excluding political opposition the bigger problem could be scaling up the service infrastructure to keep up. I think of some management games where, if you aren't careful while scaling, you have a collapse which triggers a domino effect until everyone dies. It isn't quite that extreme, but probably no one wants to turn the bay area in to a favela.
Another big question is what is the price curve where companies hire more locally rather than branching operations out elsewhere, and then when do other companies start flooding in?
The bay area/SF is at a point where it could become a major global city. It already is critically important, no question. If accessible, the capital would flow in. It may take a major earthquake before that happens.