The end game is that almost no one will own a car, and most people will use fully autonomous taxis for transportation. If and when fully autonomous vehicles become a reality, auto insurance will die along with car ownership and parking lots.
I see little reason to suppose that that will be the end game. Those for whom the total cost of ownership of a car are lower than the cost of taxis will continue to own a car.
What fraction of people that currently own cars will that be? Probably depends on where you live. Taxi will probably never be the popular choice in, say, South Dakota. The economics just don't work out.
The cost of autonomous cars, especially in terms of maintenance, is likely to be higher. And autonomous taxis will be cheaper to operate because drivers are a very expensive part of them. The number of people for whom owning a car makes sense will definitely go down when prices on cars rise and prices on taxis and public transportation drop.
This is ignoring the fact that having an unproductive self driving car sitting in your garage becomes a significant opportunity cost itself.
Shared autonomous cars would end up being treated even worse than rental cars. People would smoke in them, vomit in them, damage the upholstery, steal the radios, let their pets go to the bathroom, spill all kinds of stuff in them on the way home from Home Depot, and so forth.
Anyone who can afford it and has a place to park it will want to have their own self-driving car to avoid having to put up with the shared ones.
Ownership will also be more convenient, e.g. you can leave your stuff in your car when you park it. Your car is reserved for you to use whenever you want, so you don't need to wait for a shared car to become available.
Stick a video camera inside the car. If an ML algorithm detects anything too far outside of the norm, send the video to a human. If the human notices damage, the riders are banned from the system. Banned rider lists could be shared between autonomous taxi providers. End result: no one will fuck with the cars.
Except that we are humans not robots. You never picked up a friend after a night out who got sick in your car? Or had a baby that decided to smear poop all over the seats? Spilled coffee in the car? Know someone who likes to smoke in the car? That stuff happens, and if there was even a slight risk that it would get you banned from convenient transportation then yeah, people will buy their own so they don't need to worry about this. Pretty much everyone who has kids has to keep extra stuff in the car just in case - ergo, they will always go with personal vehicles. Otherwise, we'd see far more people switching to taxis than driving their own cars, especially compared to new cars, as monthly taxi cost can easily be lower than car/insurance/tax/fuel payments on a new vehicle, and yet people keep buying them.
