I get the lobbying source responsible for past policies. Future trends means density can be increased without space for 1 car per family, but still let people who want a car find such housing. Builders have the choice to ignore or see the future.

3-5 story "single house wide" multiplexes is affordable density compared to skyscrapers that need expensive elevators and underground multi story garage support structures. Though it is car culture/mandates that makes such affordable density impossible.