The GPL doesn't have a (meaningful) mandate that the user be able to replace the software that is under the GPL. Only that the source be made available.
This was fine in the 70s/80s when mainframes were the ruling class. Roughly a femtosecond after the market for embedded machines came along where the person setting up the system wasn't expected to have to compile the runtime environment, that died. Somewhere around THERAC-1 and the Altair.
That's why quite a few new products are still using old GPL v2 licensed software.
That "narrow" case is the entire case.
I'm currently working on a product for a well-known company and there's a corporate ban on GPLv3. And we do get audited.
For now anyway. I would be surprised if cars do not end up with apps. The car will come with the base software installed and then you can later buy apps for your car from an app store run by the car maker.
Like how macOS ships with bash 2.7 or whatever