<The Bay Area has been really bad about building>

This is largely due to politics. If you were a speculator considering building a rental apartment building, you face:

1) Rent control. (Those cities and counties that don't have it are all considering it.)

2) Requirements that you allocate a percentage of your units as limited to "low income housing", with those units becoming permanently constrained

3) permit costs, neighborhood opposition, and other city-specific barriers

4) high material prices and construction costs (e.g. earthquake and flood codes)

5) high labor costs

Of course, that won't help the folks who don't want to own a car and do want to live in SF and be part of the urban scene but there are probably a lot more opportunities for adding housing south of SF--where most of the tech employment is anyway.

Well, it won't help folks who want to live in SF, of course, but it's right on the Caltrain line. I would definitely say you could get by in downtown RWC and commute to SF if you desire without a car.