I know a lot of people at a lot of robotics companies (including autonomous cars companies), and have spoken at length with them about the ultimate business models.

Besides, it makes sense when you consider that most personal vehicles have sub-5% utilization. It's more capital and environmentally responsible to have shared assets rather than underutilizing assets with high embodied costs.

What may make sense to you and what people end up doing are often wildly different.

It's easier to make a car able to drive in a single city. Also, companies like Lyft could deploy manually driven cars for "hard" bookings.

Developing an autonomous car for Lyft is easier than developing it for a normal person.