I think this is just complacency and a bias towards how things are; imagine a world in which biking is safe, pedestrians are safe, and huge amounts of the city don't have to be devoted to parking. That's what 24/7 driverless cars can enable.
Unless you take all human driven cars off the road, you’re not going to get nearly the efficiency and safety you describe. I, for one, don’t want to live in a world where my ability to go anywhere is decided by Google and Uber. Big Tech has way, way too much power already. Please don’t give them any more of it.
Seems like a red herring. I think it’s safe to assume that you will be able to own your own SDC, and the faster Google gets this tech scaled, the sooner you can affordably purchase one.