[AndrewBissell]

There's no such thing as a catch-all "insurance umbrella." Auto insurance providers already discriminate between various makes & models. So if Teslas are actually less expensive to insure then it means every provider which is charging higher-than-average premiums is making a colossal actuarial goof.

The much simpler explanation here is the correct one: the high cost and sparse availability of parts & repair service make Teslas much more expensive to insure.