The single-pilot cockpit WILL happen eventually, just as the pilotless aircraft. The question is going to be "when?"

I don't think we'll go single-pilot for 15-20 years. It took years after the technology was proven to get rid of the Flight Engineer. The DC-10 didn't really need an engineer at all. How about the early 737s where they were run with an FE.

What will have to happen before this occurs is the flying public will have to accept other automated transportation systems. Driverless cars are in the works, but they aren't normal yet. Driverless busses? This and they'll have to have a good safety record.