A bigger problem is this: Say you need to prove to the public that the autonomous car is significantly safer, and you do an apples-to-apples comparison between a hypothetical Level 4/5 car and well designed new Level 2 electric car like a Volvo C40 or a BMW i4.

The modern Level 2 car is already today at below 1 fatality per billion vehicle miles travelled (VMT). The autonomous car then needs to be below 0.1 fatalities per billion VMT. Meaning that if you have 1 million vehicles of your make deployed, they each need to have driven 30-40 000 miles autonomously before you have enough statistics!

That means proving the safety of a Level 4/5 autonomous system is extremely expensive and slow, and requires significant public adoption before it's proven to be safe. The consequence is that, assuming proven safety is necessary before public adoption, it becomes impossible to prove safety.

Another point is that OTA upgrades for autonomy become entirely pointless, as you'll be polluting your statistics if you change the code more frequently than every ~3 years.