Even if Tesla could make them (they can't), robot taxis as a replacement for private care ownership is a pipedream if you don't first do something with the transportation patterns.
As long as the main driver for private transportation by car is commuting to work, a taxi fleet is going to need about the same number of cars as we've do today with private ownership.
It wold just add traffic: a robot taxi can't just wait in your driveway till the next day.