Tesla could insure but has generally chosen not to:
. ..A successful product liability claim against us could require us to pay a substantial monetary award. Our risks in this area are particularly pronounced given the relatively limited number of vehicles and energy storage products delivered to date and limited field experience of our products. Moreover, a product liability claim could generate substantial negative publicity about our products and business and could have a material adverse effect on our brand, business, prospects and operating results. In most jurisdictions, we generally self-insure against the risk of product liability claims for vehicle exposure, meaning that any product liability claims will likely have to be paid from company funds, not by insurance.
Products liability is not garden variety negligence (Duty/Breach of Duty); all a plaintiff needs to prove is a defect that was the proximate cause of injury or death.
Other auto manufacturers generally protect against Products Liability exposures with structured programs involving self-retained lower limits and true risk transfer to excess liability carriers/reinsurers at the upper levels.
Going "naked" is potentially an existential risk, particularly when there is "limited field experience" with new products and features.