On the contrary, I think that they might have had enough insight to see how potentially disruptive it could be if one person claimed all of those coins after bitcoin had attained widespread adoption. It also keeps someone from being able to claim the Satoshi Nakamoto "persona," which I think could only be self-serving. I don't think Satoshi revealing himself could ever do the world much good. One of the tenets of bitcoin is the lack of a central authority or leader.