How about the talented people who are exceptional at their jobs, content with their cushy lives, and stick around even though they aren't learning as much anymore? They enjoy being a trusted go-to person on many matters and stimulate themselves outside of the workplace (or with the challenges of being a middle manager).
That doesn't describe my personality, but it certainly fits the personality of some of my favorite ex-coworkers. Aren't these folks exactly the type a company wants to hire?