How about one pilot to monitor an unmanned system?
Two things pop to mind:
One, he/she would not be capable of manual flight. One cannot learn to manually land an aircraft competently without actually doing it. It'd be like watching a player piano for years, only to be called upon to play a concerto perfectly on the first attempt. So ... when the magic dies, and there's a 25 knot crosswind, and it's dark and stormy, and you get to land on a slick runway.....
Two, that pilot will have legal responsibility for the lives of the pax and the value of the aircraft. As a person's responsibility grows, so does his salary.
Answer me a simple question: you are responsible for the lives of 300 people, whether you're solo in a cockpit or sitting at a console on the ground. You are legally and morally responsible for them as they travel at 600 mph through space. And you're responsible for a couple hundred million in aircraft, the millions in high-priority freight in the belly, and the lives of all the folks you could possibly kill on short final in a crowded airport e.g. Heathrow.
What would you do that job for, money-wise? To maintain the requisite skill levels, to take the legal responsibility? Would you do it for less than what pilots make today? (In our brave new world, that's about 120k american a year.)
If you would, then you don't fully understand what you're signing up for.