Wouldn’t get your hopes up on it being 90% cheaper—typically Waymo cost the same or slightly more than Uber for me. Obviously the economics change as time goes on but I doubt they will make it that much cheaper.
Without the need of a driver, cars will increasingly be offered as a rental service rather than an ownership object. In a good month, the only expenses I pay for my car is gas, which is 150-200 USD. Do you think driverless car services will somehow be immune to the pressures every other rentier model (actual rent, SaaS, Netflix, etc etc etc) succumbs to?
There are many people that want them! There are even more than want 90% cheaper Ubers.