Switching to driverless raises the question of who owns the vehicles they'll be using, and if they're the ones owning the vehicles in their fleet that represents a major shift in capital expenses and ongoing maintenance costs.
I think if cities and states had to choose between Uber with people (more jobs) and Uber with autonomous vehicles (less jobs) they would or should pick the former.
As much as cities and states can regulating employment rules, and taxi rules, they can also regulate rules for use of autonomous vehicles. So, when it comes down to it, they don't have to choose a regulatory regime that makes either of those options viable.
You buy the car and lease it to Uber for 70% of the revenue. Same model as now, minus the "employee" factor.