To be honest comparing the insurance between old and new cars isn't that relevant either [0] (random example). The vast majority of people don't understand how insurance works and what are the criteria. Old cars are expensive to insure because they tend to be more expensive for the insurance company.

Do you really think that fixing a car where the parts are very rare and expensive, in authorized garages that are rare and expensive, while taking a very long time because there's no network for servicing will be as cheap as fixing any regular equivalent car that does have that servicing network?

Any car that's expensive to fix will have more expensive premiums. And expensive to fix usually means: it's often involved in accidents, parts are expensive, garages that fix it are expensive, takes a long time to fix. Tesla checks the last 3 out of the 4 main boxes in most regions in the world.

[0] http://www.thejournal.ie/car-insurance-10-year-old-vehicles-...