Right, so why are we moving on from the F22s so quickly? (or just seemingly so)
The F22 was hyperexpensive, and was designed for air superiority only. The belief was that the F-35 could serve for all three services and have significant air to ground capability in addition to air-to-air. The F-35 has a single engine which means maintenance should be lower cost.
The F-35 is a much more flexible concept, in theory. The F-35B is VSTOL meaning the small "carriers" can now carry significant stike assets.
It's not terribly unusual to use a type of plane for decades, or only a few years, and we still have F-22s in service of course.
The interesting development is the F-15EX, an enhanced version of that plane, first developed for Qatar of all places, basically. The F-15 was originally designed for air superiority, but they added a second cockpit and it can do significant air to ground now in the F-15 Strike Eagle version.
The B-2 may have a short run with only 20 built (21?). The B-52 will still be flying almost a century later, it's now being reengined. That is insane, but makes sense.