The AF won't need nearly as many tankers. 1st off, the huge numbers of 135s were built to sit alert for B-52s in the cold war. Today's mission is very different. Also, with UAS taking over the airspace, much fewer tankers will be required to maintain the air support which use to be done with F-??s. The "bread-n-butter" of the KC-10 was it's phenominal cargo capability--23 pallets (170K pounds). It did provide one hell of a fueling station as well. Those arguing the number of "booms in the air" are just pushing for the Boeing. Obviously, everything is political. Being a long time 10 guy and a few years in the 135, I can say it was very rare when "booms in the air" was an issue. It was much more common to dump fuel/fly fast with boards to make landing weight. With UAS now playing a dominant role, tanker requirements will be significantly less.