Not enough -10s to go around.
I keep hoping that someone will have a Wile E. Coyote moment and remember there's a shttload of 10's still out there, most painted purple of course, but there is a mod to convert 10-30's into tankers.
It wouldn't be a true KC-10, but it's a boom, it's certifiable, and it gets some gas out there until this crap gets sorted out. Hell, the way things are going, you could probably get 20 of these done before the selection process is compete.