I don't believe Tesla will pursue this business model, because there are many more cars can be sold to people who will insist on owning their own. A dialup auto-taxi system would be really cool, but as long as we insist on car ownership, subtly sold the "Freedom" of owning cars, and Tesla remains dependent on profit, creating cults of folk wishing for, or already owning Tesla cars, I don't think we'll see many auto-taxis.