Not all self driving car programs were created equal. Tesla and Uber have been acting like cowboys from the start. Most of the advanced lane keeping type setups GM supercruise and Nissan Propilot are exposed to similar risk as Autopilot, but excepting the gong show that is Uber, all the other companies developing L4 have a pretty stellar track record.

And, as you mentioned, we need to accumulate billions of test miles before we'll have statistically comprehensive data.

You can't compare statistics unless the underlying miles are comparable, though. The only miles that humans drive which should be compared are those that a given AI is capable of driving.