The problem for this particular problem is not just regulation but also financing. One has to spend money to build an ADU or convert a room to be habitable, and

The problem for this particular problem is not just regulation but also financing. One has to spend money to build an ADU or convert a room to be habitable, and most people who own homes don’t have free capital around to do that conversion. Ask your bank for a loan to do it and you’ll get laughed out of the room. The FHA guarantees on home loans have made FHA insured loans much more attractive to banks, and the limits pretty much limit loans to single family homes in high cost areas. This and the mortgage deduction are probably the three biggest distortions of the market today with zoning. https://www.theurbanist.org/2021/06/25/conventional-conforming-the-quiet-hurdle-to-increasing-density/ https://www.theurbanist.org/2021/06/25/conventional-conformi...