> It's not an issue of social mobility either, since people living in the bay area are some of the most socially mobile workforce there is.

The article focuses on non-tech workers. Who may not be socially mobile.

These areas need non-tech workers just as they need tech-workers. It's tough to have teachers work and live in Sunnyvale, where the median house price is pushing $2M. Many of your Lyft and Uber drivers will be coming in from 90+ minute commutes.