You can only build what the zoning allows, and that's what the issue is with SFH owners in big cities and how they vote. Many of them don't want to allow denser

You can only build what the zoning allows, and that's what the issue is with SFH owners in big cities and how they vote. Many of them don't want to allow denser development in order to keep those market forces in their favor by keeping housing pricing high. As soon as zoning here in Minneapolis was changed to allow for denser housing city-wide a lot of smaller multi-family units started construction almost immediately.