That remark was separate from and unrelated to the actual point I've been trying to make: there is a very significant gulf between the notion of a "self-driving car" as a form of automation built into a vehicle which is still under the control and responsibility of a human driver, and the notion of a "self-driving car" which is a fully autonomous robot built in the shape of a car, that must be capable of doing something reasonable in all situations without depending on a human. The latter is a much harder problem than the former, and we don't yet know whether it can be solved in a way that yields a practical, profitable transportation system of the sort many people like to fantasize about when they discuss (for example) Google's autonomous vehicle program.