Being able to do things to your property is one of the basic concepts of, well, property.

Let's say your car's manufacturer fixed the wheels using security bolts and they're the only people who have the sockets.
With actual cars it would be, at most, annoying. You'd still be able to undo the bolts, either by buying or making a fitting socket, or just smacking a regular one until it fits.

In the digital world, however, just because it's called a "security" socket, you're forbidden, by law, from tampering with it. And if the licensed services stop servicing the model of your car one day... You're fucked. Because, even though you "own" the car, you are legally forbidden from doing basic maintenance required to use it.