There are no parts available from anyone but Tesla. So when the $2,500 plastic lens assembly for your brakes is back ordered 3 months, the insurance company is stuck with your rental coverage.
My immediate guess is because other car companies outsource the production of most of the parts, and the companies who make those parts are happy to make more to sell on the aftermarket.
Tesla manufactures parts itself, and is still getting their main production lines working right.
Tesla does. But builds most of their parts in house. And even outsourced parts may wind up inside of the part you need to replace, and therefore you're still bottlenecked on Tesla.
