The correct answer is the cost of construction and the unwillingness to build more/higher density housing. Construction used to happen a lot more than it does

The correct answer is the cost of construction and the unwillingness to build more/higher density housing. Construction used to happen a lot more than it does now. Demand keeps increasing, but the supply isn't increasing as fast as it used to. Every homeowner who treats their home as an investment vehicle is game theoretically forced into NIMBYism so that the rich get richer.