Unless I'm mistaken, pretty much all UAV ops (standfast what the Israelis were doing with drones in the Bekaa in 82) have been in "permissive" environments. By that, I mean that there have been no large-scale or co-ordinated attempts to disrupt the control and comms systems for them.
You could argue that dedicated target-specific UCAVs would not need external info (in essence they become a meaner-looking potentially more manouevrable TLAM), but I think that case would be hard to make for more reactive (in-flight retargetable or autonomous) assets.
That pretty much imples a continuing role for manned aircraft, although whether it's a majority role is another question......