Comment by belter
If you put human lives on the line, both on the shared public road and inside the Waymo then how the sausage is made totally matters, as directly applies to what the failures modes are. Safe from A to B only holds in ideal conditions and limited zones. The hard problems like rare edge cases, weather, unpredictable humans, are precisely why it cant scale easily.
If the tech was truly solved, Waymo would not be geo fenced or expanding so slowly.
It may not scale easily but it is scaling. Waymo (Alphabet) has access to essentially infinite capital to make that happen. I predict that within 10 years the majority of the US population will have access to their rides.