Sorry, but nobody has ever shown this safety aspect to be anywhere close to true. But everyone is taking it as a gospel. Musk said it, so it has to be true, right? Never mind that there are no independent data to support it available, except what came from Tesla (who has an obvious vested interest to show that their systems are safe).
It also ignores that there are pretty much no self-driving cars on the market with the exception of some buses running slowly on pre-set lines. Cars like Tesla are not self-driving, their systems are level 2, maybe 3 at best (i.e. human always in the loop, ready to take over immediately). Then there is Waymo who is attempting for level 4, but those are still research prototypes and not commercially sold vehicles. Same with Uber. And both still have tons of issues.
So based on what are we concluding that this is going to be safer, exactly?
Given how poorly regulated the automotive electronics industry is, how opaque all those boxes are and how fierce resistance are the manufacturers putting up to even attempts to have these things opened up for inspection and certification (similar to airline industry), this is a completely ridiculous stance to take.
Especially in the light of recent scandals like Toyota acceleration problems, Tesla's autopilot crashes, Dieselgate, cars that can be hacked and disabled through their infotainment systems (Jeep ...) etc. - all of these were essentially software and electronics issues, often in much simpler systems than safety critical ones. Companies are unable to get even something like a car radio right and you want to trust them that their car won't kill you because of a memory overflow somewhere or camera misreading a stop sign? Only because a manufacturer makes such claim, with little to no verifiable evidence?
Is this the manufacturing culture that is supposed to solve the safety problems on the road? Good luck with that. That is wishful thinking while ignoring both the evidence and past industrial experience.
Even that airline industry which is much more heavily regulated, inspected and supervised than anything automotive has large problems - just look at the 737 MAX debacle.