I think there's a political dimension as well.

Part of the problem is that self-driving cars are expected to have a perfect operational record for liability purposes, but that's an unrealistically high standard.

Something like legislation that says operational standards at the level of the average human driver are "good enough" (and maybe even indemnifying companies to some extent) could probably help, though it would probably be controversial for understandable reasons. In any event, it's no more than has been done for other industries.