the rent is too high because of the market incentives. zoning laws are one of several dynamics that influence the market.
we've built a ton of structures with existing zoning laws when the economy is good, more than we've built during this deregulation paradigm. we stop when the economy or market is bad. very simple concept.
One less dynamic would be helpful then.
There's also the other turd in California real estate policy: Prop 13.