It will happen & faster than we can imagine right now. Humans solve problems & if a technology company can demonstrate the huge annual savings in training, accomodation, meals (etc.) of flight crew AND alay the percieved customer safety fears, its a goer. Arguably, 10's if not 100's of millions of dollars saved annually for an airline with 1000 pilots.
Think back 100 years. The flat earth society would have hammered the pioneering airline moguls & their 'high risk' machines. With train & steamship technology 'state of the art' at the time, of course the safety argument won over........ but only for so long. Our world is evolving faster than ever, if business leaders & boards of directors want this concept to be a reality, it will get up.
The challenge is to counter the argument in a better way, that's why I say I hope the union guys have this on their agenda. It won't be a technology argument, it will be a marketing campaign fueled by cost savings.