True. But if you listen to his interview it is clear that he is neither pessimistic nor optimistic. He recognizes that unanticipated breakthroughs are likely. His point is that there are too many unsolved problems for a quick development of useful driverless cars. He goes through the issues in some detail, but to offer one: real world drivers need to break the law all the time in order to not get stuck in traffic. How do you decide when it is OK to break the law? Who will accept the liability associated with a car that sometimes breaks the law. Etc.