How do you know that a car is the result of a properly designed system before you get behind the wheel (or step in front of it?).

>the only real fear here is a state-level attack

Why isn't this a valid concern? We should just be fine with russia or china having the ability to remotely hack all of our cars and kill/spy on individuals, even critical members of our leadership? What about our own government? What about some terrorist launching formerly state-level malware from his basement with the help of AI?