I think at this point it is clear that main problem with self-driving cars is not technology but social, psychological, political and legal challenges. People often forget that having good tech is just one step that does not guarantee any commercial success.

People dont change their habits just because new tech is available. People are not going to start buying or using self-driving cars just because tech is available. There is huge psychological and social environment around car driving - e.g. think about all legal paperwork you have to go through to start driving, learning how to drive, buying insurance, all traffic regulations. All this cultural/human factors are based on specific definition of what car is and they all rely there is human subject operating this car. If self-driving cars are really going to succeed all this huge extremely social framework would have to change. I don't think this will happen. I think there are simply too many strong human emotions and purely financial interests around cars.