This kind of stuff is actually what is less likely to make me purchase a Tesla. If it becomes common for these kinds of failures, it isn't a risk that I want to have.
What is magic about annual maintenance? In my gasoline car, I change the oil around every 7500 miles (when the car tells me) and rotate the tires at the same time. Total cost about $50 a year. Brakes when they need it for around $200, and when I need it four tires for a little under $1000. Throw in a yearly emissions and safety inspection for $37.
Most gasoline cars will have a 5/60, or 10/100 powertrain warranty. But even outside of warranty, I know I am not going to have to pay $15,000 to fix it. I'm also not stuck going to the manufacturer, price shopping is possible and I'm sure would save money over a dealership.
That is why it should be inspected, to catch problems before they become serious.