Earlier quoted context omitted.
> exhaustive logs of Autopilot disengagements That would still be only one slice of the many many situations you need to master, and that Waymo already has. E.g. something as simple as entering and exiting a small roundabout, like that YouTube video showed a Tesla couldn't do. Miles driven by Tesla owners aren't purposefully looking for those situations when they engage autopilot.
Are you sure? Again this is just how I'd do things, but after I had a bunch of disengagement snapshots, the next thing I'd do is start taking snapshots of similar situations. We live in an age of easy and super-accurate image classification, it wouldn't be too hard to start a snapshot every time the front camera view contains a roundabout.
With how long commutes are in the US, a very very small fraction of miles driven by people on autopilot will be other than "the car was already on the highway, autopilot changed lanes a few times, and after a while was manually disengaged to take an exit".
That small fraction is what could be compared with the miles and number of cars driven by the other companies, because in the latter case it's hired drivers actively looking for conditions of interest to the engineers.