Thats been debunked many times, the current data doesn't support the argument at all. Musk doesn't want to acknowledge the truth in this regard as it's not on message.
His argument is "cars on autopilot do more miles between accidents than cars not on autopilot"
The counter argument is "autopilot is most commonly used on the safest roads and the safest times in the safest weather and drops out if it can't cope, the other measure includes all roads, all conditions and at all times including snow, ice, complex junctions, busy streets. etc". I think UK motorways, which are probably when APO is used most, are statistically 4 or 5 times safer than average, so autopilot should be 4 or 5 times safer than "all road driving" to reach parity with humans on motorways.
The acid test is, if you believe autopilot is better than humans, why would you ever try and drive a single meter without using it?
The thing that makes me think they won't is the liability question. Level 3 moves responsibility away from the driver. The litigation that will follow in the event of an accident will be enormous. In Europe we're saying the insurers will be responsbile, maybe you could argue insurers pick up the tab anyway but they'll need to be happy its safer. And people will still sue Tesla for defective software. It's massive legal hurdle I recon and I wouldn't be surprised if Musk knows that which is why he's trying to set up his own insurance company.