Something more is necessary if "self-driving" is going to actually live up to its name at some point in the future, and I don't think the answer is 100% software.
At this point it's all about edge cases. Certain edge cases are impossible to overcome with just software + cameras alone.
Most humans can drive fairly well in heavy downpour, solely from the brake lights of the car and occasional glimpses of road markings. Thats almost equivalent to a very poor sensor suite.
At this point it's all about edge cases. Certain edge cases are impossible to overcome with just software + cameras alone.