Maybe if there are no competitors. Even as monopolistic as the military aircraft industry is in the U.S., drones open up a lot of space for competition by being vastly cheaper.
Then there’s concern about long-term sales to foreign countries, plus the corresponding parts and maintenance revenues. The F-16 is flown by 25 other countries.
The U-2 first flew in 1955. One was shot down over the USSR in 1960, and another was shot down over Cuba in 1962. They largely stopped flying over peer air defenses at that point.
That’s about a 7-year span where it was useful for its primary task. Hanging around to fly over Libya in 2011 is not the same as fulfilling the role the plane was designed for decades later.