[jeffbee]

This is the utilization theory of dwellings, which I think is bunk. Actual utilization is over 90% in California cities, so fiddling with vacant and underused properties can only make a small difference while being rather difficult to achieve. 10% vacancy is actually desirable because it makes the marketplace work.

Land, on the other hand, is severely underused. Zoning changes could easily triple the housing supply in American cities. That's a lot better than 5-10%.