Do y'all realize the F-15 is 51 years old? That is, since its first flight in 1972.
So we built the F-22, once again tried to stuff multiple missions in one airplane, with Stealth added, and now we are buying more F-15's. Have we ever done that before?
Note we are still building F-16's as well, and it is only about 4 years newer than the F-15.