There will be a natural monopoly (or rather, a natural oligopoly) once the car makers all have their own autonomous carsharing fleets and sell cars only with an EULA that forbids ridesharing. The entry barrier for car manufacturing is way higher.
>sell cars only with an EULA that forbids ridesharing.
It'd probably be leases, rather than sales - selling property gives the buyer more rights, which would make that sort of EULA problematic. Might be able to side-step it by a combination of forbidding commercial ride-sharing in order to keep the self-driving system up to date along with requiring up-to-date self-driving software to be road-legal.
Ok, but a lot of companies are working on self driving cars.
If one company refuses to sell self driving cars to consumers/upstart ride sharing companies, then that means that ANOTHER self driving car company can makes 10s of billions of dollars by ignoring this rule.
Do you really think that not a single one of the multitude of self driving car companies would break the collusion agreement, if there is 10s of billions of dollars on the line?