The answer is, they are, but we have aging airframes that need to be replaced now. That is basically the F22/F35 right now. The F15/16/18's won't last forever,

The answer is, they are, but we have aging airframes that need to be replaced now. That is basically the F22/F35 right now. The F15/16/18's won't last forever, and most early block number airframes won't survive the transition to drones. This is really no different than past fighter replacements. Like the F80->F86->F104->F4 etc... (i'm intentionally skipping planes). Actually the F4 is a great example of where the accepted "future of air combat" was proven wrong. As it turns out missiles weren't the best idea for the only armament on an aircraft. Drones may end up in the same category and we still want manned fighters, we might not yet want to go whole hog into as yet unproven territory.