If there were a fleet of a million Waymo cars, 2,000 support staff, and 2,000 engineers keeping a stable technology running, and vehicle wear and tear was low (possibly lower than a human driver running an ICE car ragged)...it could work. But they're going to be unprofitable for a long, long time.
It's hard for me to believe that Alphabet/Google even wants to be this huge robo-taxi service in the long run. I have to believe they want to be a technology supplier. Which means they need to enable robo-taxis-are-us to be a cheaper taxi service than Uber et al.