If those rental cars are going to be around, and if people want taxi apps because they don't own a car then there's two applications for self-driving tech.

Public transit is great, but it works best for dense areas along busy routes, and there's always people who want to go direct without transferring, or walking to a station. Suburbs and rural areas won't be relying on public transit, the activity is too low.

Self-driving cars lead to fewer deaths than human drivers, they will eventually be cheaper to insure than human drivers, and summoning a taxi without a person will be cheaper than one with one.