I'm not talking about technical viability! I'm talking about product viability. Can this hypothetical device be manufactured and sold for a profit? Can it be used, profitably, for some purpose, for which it will be cheaper or in some way preferable to existing solutions? It is not enough that this autonomous car can drive around the block without crashing; it has to be good enough, reliable enough, efficient enough, that you can build a profitable business around the unique service it can provide. That is much harder than simply passing a standard driving test.