The self driving bit has to be nailed down first I think, once that's done nothing I've described is even remotely difficult to implement, it's more a matter of peoples thinking around driving evolving.

I think it might go this way because people feel like they want to "own" their "cars". Especially in America it's a big part of the culture, so I can see being able to buy the coach part as being a popular compromise.

Powering electric cars is already cheaper, but right now they're less convenient, with self driving they become as convenient or more than gas vehicles. You no longer have to stop and charge anywhere because there's a fresh "horse" waiting to be hooked up while your existing one drives off to a charging station, all the downsides are automated away.

BYD is doing something related in China. They've got a fairly popular battery swapping service that can swap in and out batteries of different sizes.