You're right. That IS the most important question. But you pose this as though the only concern is jobs. What if you knew that humans behind the wheel of motor vehicles are on pace to kill 37,000 people this year in the US alone, and vehicular deaths are going UP this year vs. previous years..
The mistake I think most people make, is they're totally fine with 40,000 people a year dying in cars due to human error, but they can't tolerate a SINGLE fatality in an autonomous vehicle.
You bring up all the modalities of electronic failure. But you minimize the fact that humans get fatigued, high, drunk, inattentive, angry, distracted, etc. and cause mayhem that way, and autonomous vehicles won't.
There are only a handful of driver less vehicles out there and there have been at least two deaths.
Software glitches. A sensor goes out on a driverless car and suddenly doesnt see the stop sign up ahead.