I have always been amazed (in a bad way) at the quality of the work done by service departments at luxury and high-end car dealerships. I'm not sure what kind of agreement these independently-owned dealerships have that they're allowed to use the manufacturer's corporate identity to promote their business, but it should be a whole lot stricter.
Conversely, I've never had my laptop receive a shoddy repair at an Apple store - after all, the repair facility is owned and being operated by the same company who built the machine in the first place, so they share common goals and incentives. If Tesla is trying to do for car dealerships and service centers what Apple did for high-tech retail, the privilege of participating would definitely be worth $600/yr to me.
Now, Apple does have a licensing program in place to certify independent repair facilities as "Apple Authorized Service Centers" where warranty work can be performed. I think Tesla would do well to create a similar program, and maybe they plan to! Who knows, it's early days yet.