For most (not all!) of that complexity, if it fails you're left with an inoperable part of the car, not an inoperable car.

I've got a 2011 Hyundai that's...well, it's got all sorts of problems, most likely caused by the chipmunks that call it home . The backup camera doesn't work and stereo system is silent.

But the car still drives just fine, those systems don't cause a full failure of the vehicle. The screen goes black when backing up of course, but I can still back up.