We have four types of folks here in the U.S. as far as living situations are concerned:
Urban: Folks living in densely populate cities such as New York and Chicago (among others);
Suburban: Folks living a fair distance from the urban areas (up to 30 miles or so). This is where the majority of our population currently live;
Rural: The entire midwest and almost all of our farming/ranching lands, plus everything in between;
Hermit Crabs: There are still some very back-woods folks here, and many of them would rather shoot you on sight as look at you.
This whole "auto-car" thing makes some
sense to exactly the first category, and zero sense to everyone else. "Public transportation" is not a thing for the vast majority of Americans, and for several reasons, the most obvious of which is that the U.S. is a nation of sprawlers that want to be on their own back forty and nowhere else. Here in Boise the idea of a rail system has been floating for 20 years, but with no place to put it because the entire area is already paved over and built up. There was a solution available 15 years ago, but no one listened to me, so screw them!
Busses work in some places (like Phoenix and Portland) and don't work at all (Like here in Boise, where the bus system has been so politicized as to be useless). Kid you not, there is a section of the road our shop is on where the bus literally goes 1/2 mile out of its own way to avoid serving a mile of road due to an ongoing dispute the bus system's owner has with a small business on that stretch. "Agree with me or I will divert my busses around you!" And, since the bus company gets to determine the routes by contract, the city is powerless to fix it.
Even setting that aside, our bus system is a useless turd that serves only the desperate; a bicycle is faster and more reliable, even in the winter!
I'll let others speak to their own situations, but I lived in Portland and Phoenix and could use public transportation in a pinch (at least so long as I didn't need to be out later than 10pm-midnight — but that was years ago; I have no idea what the hours are like now). I do remember that if I got off work later than 10 I was on foot.
Auto-cars might solve some of that (again, in densely populated urban areas), but the majority of the population are going to be woefully underserved by such a system.