The chance that the USAF could source a new designed F-16 replacement that costs less than an F35A is precisely zero. By the time the USAF got through with everyone's wish list, the resultant aircraft would be twice the size of the F-16 and cost four times as much.
Heck, it was a bit of a miracle that the F-16 made it - and even it ended up nearly twice the size and weight of the original concept.
My experience on the 767-2C/KC-46 was quite the eye-opener. While Boeing certainly shoulders much of the blame for that fiasco, the contribution of the USAF brass was far from insignificant. We started out with a 767 - which was a fine, very successful aircraft - and the USAF seemed intent on totally mucking that up. Trying to explain to anyone in the USAF that a requirement was simply non-sensical - adding great complexity and cost for zero value added - was an exercise in futility.
Remember that cartoon of a camel being a horse designed by committee? Who ever came up with that had probably dealt with the USAF...