I think the manufactures will sell cars to those want to run a taxi company. This is, and will remain a race to the bottom because competition is fierce: people buy price and first to get to them.
They will also sell cars to normal people. Most people don't think about how convenient it is to have the storage of their personal car. If parking is free or cheap (which is it in the suburbs) having your golf clubs in the trunk or a spare diaper in the glove box are worth the little extra cost, not to mention your car is always there so no need to wait for the taxi to in busy times.
Of course there is also the city, but if you live in a city self driving cars still suffer from congestion and so public mass transit still has big advantages. In fact because the self driving taxi is spending time empty waiting for the next rider it adds to the problem meaning for even more people public transit is worth the hassles with it (which in turn means more demand to make transit better)
A self-driving car is software and hardware... you can sell hardware but software only gets licensed. Software is really where the value is, and that won’t be owned by anyone but the company that made it.
Look at the history of mobile phones, which were originally sold to consumers only by the carriers. As the phones got better and better software, the business model attached more and more to the manufacturer.
On the way something like UberPool would be needed. Or the taxi can just drive me to the nearest train station and I can take mass transit into the city.