[BluffTHIS!]

fim, now I will actually get on topic instead of bashing. I think that the answer to your question, in addition to those things ML4 discussed, is that what separates good even expert players from great players, is their thought process in evaluating a situation and what things they think about. That, combined with technically accurate knowledge, both mathematical and otherwise, that can be found is error-free books, is what elevates them. And besides their playing proficiency under a wide variety of game conditions, they also excel at bankroll (not money) management. All of these things are covered to some degree in Barry Greenstein's new book, which despite the fluffy color photos is well worth reading.

Also I think that it is true that many of those top players have in the past lurked/read here a lot, just not posted. In fact I believe it possible that the lurker/poster ratio could be as high as 10+/1, most of whom don't feel competent enough to post, but also including very good players who are just selfish and want to take but never give.