First off, you may not want to repair your own car but the practice is pretty widespread, at least with simpler repairs. That's why the US has four nationwide

First off, you may not want to repair your own car but the practice is pretty widespread, at least with simpler repairs. That's why the US has four nationwide auto parts store chains plus some big box stores like Wal-Mart that carry parts. Second, this is not just about shade tree mechanics. This type of vertical integration means you have a sole source for parts and work if you buy a Tesla. Tesla can thus charge as much as their customers will bear without driving them to buy someone else's car. They have no incentive to pass supply chain or servicing efficiencies on to their customers. It's an arrangement the other car companies only dream of, which is why they keep trying to throw roadblocks in the way of third-party mechanics and parts manufacturers.