The honest argument is that we’ve seen Tesla’s technology in unsupervised and uncontrolled adversarial conditions across hundreds of wildly diverse cities in the USA, whereas we haven’t seen Waymo do anything other than narrow geofenced areas or curated marketing videos. Right now if you dropped a Waymo and a Tesla in Michigan, one of them will drive at least as well as a human learner driver and the other will probably refuse to move at all.

I agree that Waymo could well be far ahead of Tesla. With the information at hand I don’t have a way to make an assessment either way.