@RegalBeagle I theorize that much of the suburban expansion was motivated by Cold War fears of nuclear war, with spread out cities being done in effort to reduce death per location bombed.
Regardless of whether that theory has merit, you are correct that we are not going to be able to change city designs to be less car centric with our low trust society. Many shills for "walkable cities" simply ignore the critical component of high trust (and most often homogeneous) population first.