muduckace,
There is a world outside nice and homogeneous USA. Here in Europe there are 50 different countries in roughly the same geographical area. Different languages, culture, attitude towards safety and regard for human lives. ATC controlling aircrafts will never happen, thus there will always be the need for someone in the aircraft to take (and evaluate and possibly decline) instructions from ATC. If one guy is needed, there has to be a backup in case he becomes incapacitated or dies. Hence, 2 pilot crew will persist for a foreseeable future. I doubt there will be a change to that in our time.
In fact I think this is as likely as world peace.