The bay area has the greatest social mobility in the US: http://www.equality-of-opportunity.org/
You're not going to see a Tenderloin drug addict or one of the Mexican day laborers waiting outside Home Depot make their fortune here. Nor will you see someone like Kevin Rose reduced to working at Burger King, however much value he destroys.
Your original comment was very much on the mark.
That's pretty significant. In a small town in Minnesota, people won't follow that path because it would be completely outside their experience. Not so here.