Some cities already have a "spread out" landscape in which it's impossible to go anywhere without a car. School? Needs a car. Grocery store? Needs a car. Want to switch a lightbulb? Needs a car. Human lifestyle won't change unless you change the human environment. Humans might go so far as to run into a burning building to save a pet because it gives an immediate return. Saving the environment don't have immediate returns. Human brains aren't wired to make those types of sacrifices.
Of course the vast majority of car miles are done going to place of work. Public transport is the answer, but it would need subsidy to get started and commitment of a substantial number of people to make it pay for itself - you're right, it ain't gonna happen.
Technology to utilise solar energy and have electric cars which are quiet and don't pollute will be the probable solution.