Has anyone done some math on the housing density that is most economical? My guess would be that the height limit would be close to five or six stories before the engineering to go higher was excessive, but that is just a wild guess. Courtyards down to ground level so people can have an external view seem wasteful from a heating and cooling perspective, most people don't want to live with no windows.
The real solution would be to fight the speculation and accept acces to a home as a human right. So prohibit/tax unrented rentals, progressively taxes owning multiple homes.
I live in a poorer EU country where foreign money bought everything they could. They dont even bother renting it out because increase of the value of the properties is where the money is. If they started to rent the evaulations would fall.