I’ve seen EV’s characterized as phones on wheels before, and as an owner that seems apt. I envision a hobbyist community for old EV’s developing much in the same way there are groups that tinker with TRS-80s and Apple 2’s. Once support for a platform ends, someone will find a way to root it and then install such mods as seem cool or fun.
I think it would be more like the car maker couldn’t be held liable for what the car did if the car was hacked. And good luck getting insurance to cover you if you wrecked your car after hacking it. It would be a strictly at-your-own-risk proposition. And if you hurt anyone else driving a hacked car, woo buddy.