To me, it's turtles all the way down. A three letter state agency isn't going to be stopped by the tamper resistant packaging on a Tylenol bottle and it's probably easier for a criminal or a military to just shoot their victim [at least in the US]. Disabling the victim's vehicle with software is a bit Rube-Goldbergian and a psychopath doing it on a mass scale just for the lol's could just as well poison a water system.
Industries at the scale of the automobile industry are always making actuarial bets on fatality rates. Software or hardware or mechanical or digital is irrelevant, e.g. GM cheapening ignition switches without changing part numbers. Anyway, brakes have been digitally controlled for many many years. Avoiding that means no traction and stability control systems and the ordinary hazards [e.g. hydroplaning] that those mitigate are orders of magnitude more likely than my car getting hacked.
Industries at the scale of the automobile industry are always making actuarial bets on fatality rates. Software or hardware or mechanical or digital is irrelevant, e.g. GM cheapening ignition switches without changing part numbers. Anyway, brakes have been digitally controlled for many many years. Avoiding that means no traction and stability control systems and the ordinary hazards [e.g. hydroplaning] that those mitigate are orders of magnitude more likely than my car getting hacked.