Earlier quoted context omitted.
Tesla uses a pretty different architecture from the dumpster fire that was OnStar. And probably other manufacturers will use their own designs. Unfortunately, this is one of those issues where we have to be lucky every time, and the bad guys only have to be lucky once. Given the number of different manufacturers whose systems have demonstrably been compromised in the past, the odds of avoiding catastrophic compromise…
I guess we should just give up and leave everything wide open then right? No point in trying to do defense in depth if someone will eventually hack something?
One plausible alternative is that we don't deploy systems like this, which have the ability to cause widespread damage including loss of life in moments, until we have worked out how to secure them properly against a single point of catastrophic failure like that. There are things that could be done to mitigate that threat in the meantime.
This is set against the knowledge that existing human-driven vehicles are involved in many tragic accidents per year, also causing widespread damage including loss of life. But there are other things that can be done to limit the damage there as well, without relying on autonomous vehicles as a silver bullet.