In the future? That's a hard question, and I'm sure however the legal system deals with it first will be wholly unfair and illogical. It'll be a battle between car owners, manufacturers, state and federal bodies, cities and counties, certification and safety agencies, etc.
The point is, regulations are not set in stone. Companies can advance the state of the art, and ask the government to regulate less strictly.
As it stands now, self-driving cars are a research project, so we'd expect them to be regulated very strictly. As testing shows them to be safe, then we can relax the regulations. If self-driving cars without a supervising driver end up being safer than a normal car with a normal driver, it would make sense to not require a license. If an accident happens, it happens. Car accidents are nothing new.