The problem with American cities is NIMBYism: existing property owners are the ones with control of the zoning and the approval for new construction. So SanFra

The problem with American cities is NIMBYism: existing property owners are the ones with control of the zoning and the approval for new construction. So SanFran can't replace its too-small housing with lots of high-density high-rises because the people who own the other land there don't want it. The fix for this is to move control of zoning and construction permits to the state level.