Why can't we just build a little farther? I am not local to the area (as you can probably tell from my name) so I'm not trying to criticize anyone. I am genuinely curious if that is a possibility. Also I've never bought, sold, built a house. Are these single family zoning everywhere?
The Silicon Valley area is surrounded by either hills or ocean, so "a little farther" is a difficult commute with varying delays of hours on a couple roads.
Nobody wants to raise a family in Oakland.
Also, my understanding is that the Central Valley is a flood plain.