A quick search came up with this site:
http://www.lewis.army.mil/transforma...y_with_uav.htm
A quote from the site is as follows:
"Seven people are needed to operate the UAV: One person to work the payload, another to control the UAV, a mission commander, an external pilot to launch the UAV and three ground handling personnel to prepare the UAV for flight."
Discounting ground handling and payload specialists, who are also required by airliners, that leaves 3 people operating the thing. It flies in open, uncontrolled airspace without the need to interface with other traffic. Can you imagine the complexity of having little groups of drone operators scattered all over the World, as their machines are entering the stack at LHR on a foggy January morning? Far easier, and cheaper, to stick a couple of people on board the aircraft, with a radio to talk to a local contolling authority.