Is it really that they "run out of steam" before finishing their projects? It seems to me that they finish all the interesting problems of the original project and are distracted by an even grander problem that still has unsolved problems. The original project's interesting problems have usually been solved and all that remains is mundane crap.
I also think the extended periods of melancholy are avoidable. After all, the BBM is melancholic because the real world he has to deal with is phony and filled with bullshit, not because he gets a kick out of wearing black lipstick and posting emo entries to LiveJournal. So what's the solution? Save him from the phony bullshit. Put him (or yourself) in an environment where he is stimulated and working on real problems without having to play society's idiotic games. Academia is my standard example of this.. there's just a lot of hoops to jump through to accomplish nothing, and the metric of GPA doesn't actually correlate to anything useful like "knowledge acquired" or "mastery of the subject", but instead reflects the amount of busy work done by the student. Learning is simply a happy side-effect that might happen while maximizing GPA. Even professors seem to spend a big chunk of their time just producing "epsilon papers" that contribute nothing other than an impression that the professor has been busy. </standard academia rant>
Anyway, put the BBM in a suitable environment and they'll be melancholic less of the time. I think.
I'm sure it differs for each person, but personally I'd say the most important things are: get out of academia, get freedom, find a satisfying job with interesting problems and management who are technical, and work on interesting stuff in your free time.
I also think the extended periods of melancholy are avoidable. After all, the BBM is melancholic because the real world he has to deal with is phony and filled with bullshit, not because he gets a kick out of wearing black lipstick and posting emo entries to LiveJournal. So what's the solution? Save him from the phony bullshit. Put him (or yourself) in an environment where he is stimulated and working on real problems without having to play society's idiotic games. Academia is my standard example of this.. there's just a lot of hoops to jump through to accomplish nothing, and the metric of GPA doesn't actually correlate to anything useful like "knowledge acquired" or "mastery of the subject", but instead reflects the amount of busy work done by the student. Learning is simply a happy side-effect that might happen while maximizing GPA. Even professors seem to spend a big chunk of their time just producing "epsilon papers" that contribute nothing other than an impression that the professor has been busy. </standard academia rant>
Anyway, put the BBM in a suitable environment and they'll be melancholic less of the time. I think.