> with the implication that this is an alternative to car ownership and would vastly reduce the number of cars
The point I was trying to make is that you need very few idle cars on top of the ones in active use. A fraction of what suburbs already have.
It could be a vast reduction in the number of extra cars over the peak concurrent number.
> I agree although things like Uber and Zipcar have already reduced the need for lightly-used second cars which are what I mean by marginal cars.
Somewhat, but self-driving cars are more effective in multiple ways. They don't need to be nearly as cost-effective while idling, and they can come to your doorstep instead of making you walk to them. There's nothing like a zipcar near me.
> Very few people would argue that having the option of owning a vehicle capable of safe fully autonomous operation (with manual override) is a bad thing. We're just saying that having full autonomy only available as a third-party taxi service just isn't very interesting relative to today except perhaps at the margins.
I think it goes well beyond the margins if the price works out. Or maybe your definition of "margins" is a lot bigger than mine in which case we agree and even a change at the margins is a big deal.
But also, even if the average person wouldn't switch, that's different from it being utterly impractical to switch.