Really? Which car manufacturer officially provides you a root access to your vehicle?

It’s almost like there’s no market for this because it’s a silly thing that practically nobody actually wants enough to vote with their wallet.

That, or no company wants to assume liability. In which case, go whine to your local representative. That’ll be hilarious for all involved.

Even as a well trained software engineer who works on transportation software including ECUs (heavy equipment not cars), I'm not sure there is much I could do with root. IF I had full source code to my car's radio I might try to add android-auto back in (it has android-automotive so I know it can do it), but if that isn't easy I'd probably give up. Without source code and a lot of time doing anything is impossible - as anyone else who works on complex software knows.

Maybe 0.1% of consumers even know what "root access" means.