[ianhawes]

Presumably:

1. Satellites can now conduct imagery intelligence at a similar or higher quality without alerting targets, conducting refueling, or risking pilots.

2. There are more satellites with higher maneuverability than before.

3. Unmanned high altitude drones will replace the existing U-2S role in the next decade or so; or already have. Consider the U-2S role in the Chinese balloon incident. The military wanted intelligence on the balloon that would not otherwise come from a satellite and therefore utilized the U-2S.