Perhaps this is an Airforce/Fighter Jock fetish with speed? The A-10 isn't a super-fast super-maneuverable sexy jet, and they'd rather have more F-22s/F-35s with all of the checkbox Nth-generation bells and whistles (stealth, super-cruise, etc)?

It's like an MVP product that serves customers vs a product loaded with features that only the developers wanted. The A-10 is boring and simplistic and old tech. Forget the fact that the F-35 is expensive, buggy, not the best in any category, and gets owned by earlier generation jets.