I live in SF (from Phoenix, AZ), but I agree, I don't think a particular locality really matters. The Internet has made remote development possible for most startups. In fact, if Kernel.org (Linux) was considered a startup, it's a project founded by people not from a single city.

I understand to some degree the reasons startup people want people within 20 miles of them. But if somebody is happy living in Anchorage, AK, why should I convince this person to move where I am, as long as GH issues are being punched out?

That said, I love SF, motorcycling to Marin, and I don't think I'll move anywhere else for the distant future.