> I've seen it repeatedly asserted that electric cars are so much simpler than ICE cars that their reliability should be much higher

That's only one side of the problem out of many. It has more to do with the general attitude and culture withing the company, which ultimately stems from wider culture.

Tesla is currently enthusiastically repeating all of GM's failures with their engineers screaming murder, and being dismissed.

https://www.google.com/search?q=tesla+welding+cracks