People become unproductive for many reasons, maybe they just didn't keep their skills current, maybe they are disillusioned, maybe they weren't ever that useful to start with and got the job by other means. But such people are impossible to fire under normal circumstances. So a good manager "promotes" them to some meaningless post to get them out of the way. Then that manager leaves or moves, and someone who doesn't know the score comes along and decides that hmm, maybe the VP of Paperclips could be reassigned to VP of Operations. And now we have an utter incompetent in a position of real power.