I actually think we should be asking more of safety regulations here with regards to the design of electric/computerized cars.

Think of it this way: every concern you have about a teenager having root on their electric car is the same as any sociopath hacker (AI enabled for modern nightmare fuel) who finds a root vulnerability and decides to not be a good person with it. If a teenager can mess with the collision avoidance, e.g. Israel can modify it to murder anyone who talks shit about Israel in the car. Or the CIA could turn it into a weapon. Or one day some dev could push a bad OTA update. Et cetera. Our safety regulations should mandate design features to prevent a malfunctioning computer from posing any greater safety risk than any other modified part in the car.