HTB,
Rather than the simple comparison of "3 crew on Reaper vs 1 in F35," a better comparison might be the total footprint required.
How large is the TGRF, how many pers do they have at KAF, and how many hours airborne per day do they generate?
Then compare that to the size of the Reaper Force, the number in theatre, and how many hours airborne they generate.
Pretty sure that there'll be a considerable manpower saving when you look at it like this. Unmanned stuff seems mostly about efficiency; your entire Force can fly combat missions every day, with no need to deploy, carry out pre-det training, no need to be away from family, etc etc.