Earlier quoted context omitted.
> So if a pacemaker has a bug, it's still overwhelmingly better than the baseline scenario of "no pacemakers." Unless it goes of when it's not needed and kills you.
Right, but the probability of you dying because you do have a pacemaker is (in the situations for which a pacemaker is prescribed) far less than the probability of you dying because you don't have a pacemaker. The same cannot yet be said about "self-driving" cars.
That assumes the pacemaker works more often than it doesn't. (Which is the case now.) It's an unstated assumption that doesn't always apply when generalizing your example.