I don’t think “walkable” cities is an answer to anything. Walking is hard for children and the elderly. Public transit is SUPER slow. If cars fit on the road, then people will use cars. They are just a superior traveling experience in almost every way.
Walkable city doesn't mean you can't have a car, it means there are other (often faster) transport options and amenities within easy travel distance without a car. Children and elderly can still be transported by car.
We have a lack of imagination when it comes to cars. (That, and market-driven commercial interests.) "Cars, but electric!" to deal with climate change. "Cars, but autonomous!" to deal with...what? It's not clear what problem self-driving cars are meant to solve that mass transit couldn't do much better. And this idea of a white light is nuts, for the reasons others have given in comments. It just shows how far off the rails we're willing to go (pardon the pun) in attempting to stick with car-based solutions.