I think it's much more likely that insurance companies have the long-developed expertise to assess the risks and actual claims experience of insuring whatever it is they insure. It's the primary thing that allows them to earn a profit. And so if they all think that Teslas are higher risks, they are probably right.
Also there might be real numbers on the costs. Like cost of repairs and during unavailability period cost of rental vehicle if such coverage is included. Specially later I have understood has at times been issue. So if you need to pay your customer to have rental vehicle for weeks or months while car is waiting for parts at shop it does have an effect on premiums. And it absolutely should.
But that hypothesis doesn't explain the large price difference between the companies, which in both cases are underwritten by other companies with long-developed expertise.
It could also be that Tesla is just willing to take a smaller profit out of the business, relative to others.
That doesn't really jive with the fact that the S-Class has cheaper insurance rates despite being a more expensive car and whose ownerbase typically consists of very rich people.
