Money aside, it is much easier to get someone from the south to move to the coasts than to get someone from the coasts to move to the south. This is especially true if you are not white, male, straight, and protestant. While I'm sure there are some awesome black lesbian atheists in Birmingham, those of us who are from outside the area are quite wary to move there.
My home (Arizona) has a similar reputation now with the SB1070 flap, and make no mistake, it has hurt recruiting.
Hell, I'm white, male, straight (ok, and an atheist), and I wouldn't want to move to the South...
But face it, there are significant "network-like-effects" in places like Silicon Valley. The talent (and money) tends to congregate. Not saying there's no talent, or strictly lesser talent elsewhere, but you can't argue with reality.
My home (Arizona) has a similar reputation now with the SB1070 flap, and make no mistake, it has hurt recruiting.