If you simply switched to automatic driving, what you would have is fewer cars being driven more often and so being worn more quickly
At the very least, I expect that would be offset by some amount by the fact that automatic cars are going to be driven in a much more efficient and car-friendly manner than they are when a human is operating it with their imperfect motor skills, their ego, their laziness, etc. The way the cars operate would be (or at least could be) algorithmically optimized so that all those little things you're encouraged to do (like pretend there is a glass of water on the dash when you're driving, etc.), actually happen.
Also, once Jiffy Lube starts accepting driverless cars, you would see oil changes and maintenance done on a more regular basis since you wouldn't have to drive it to the shop, further extending the lifespan of the vehicles.
Oil changes can easily be automated. Electric vehicles? All they need is a parking spot to automatically pull into and charge at until required to move to their next waypoint.
At the very least, I expect that would be offset by some amount by the fact that automatic cars are going to be driven in a much more efficient and car-friendly manner than they are when a human is operating it with their imperfect motor skills, their ego, their laziness, etc. The way the cars operate would be (or at least could be) algorithmically optimized so that all those little things you're encouraged to do (like pretend there is a glass of water on the dash when you're driving, etc.), actually happen.