It wasn’t any kind of collective decision to reject human scale cities, it was a campaign by car manufacturers. First, they conspired to destroy public transit, then they capitalized on the teen angst of the boomer generation to create one of the most successful marketing ideas of all time: the car as a vehicle of freedom.
That’s it, that’s all it took. Teens everywhere started watching the calendars until their 16th birthday, dreaming of the freedom cars would bring them. An escape from the prison of adolescence.
We built a world far too complex for any of us to understand. But then, the natural world is like that as well, once you look closely. I don’t think cynicism will help, but you do you!