> Yeah we don't need to compare robots to the best driver or human, just the average, for an improvement.

Sure, in theory. In practice, nobody is going to give up control on the basis that the machine is "slightly better than average". Those who consider the safety data when making their decision will demand a system that's just as good as the best human drivers in most aspects.

And speaking of Waymo, let's not forget that they only operate in a handful of places. Their safety data doesn't generalize outside of those areas.