It's a matter of defining "full self-driving." If you're accustomed to horses and see someone selling cars, it'd be reasonable to say, "Those are ridiculous. T

It's a matter of defining "full self-driving." If you're accustomed to horses and see someone selling cars, it'd be reasonable to say, "Those are ridiculous. There are numerous places only my horses can reach. There will virtually never be a time cars fully replace horses." And you'd be right. It's still true--there are places horses can reach that cars cannot. But because of the value of cars, society has reoriented itself such that reaching those places doesn't matter to the vest majority of us. I think self-driving cars will be the same. We don't need them to operate in every single road / circumstance ever. There may always be roads that self-driving cars can't drive on. But it'll become irrelevant because the vast majority of places people want to go will become navigable by self-driving cars, whether through the cars getting better or the roads becoming more easily navigable.