If it's just "how not to lose" now, I think that has a lot to do with the degree to which its messages have already been absorbed into the mainstream to the point that it'll only bring you up to what other people in your field "ought to know." At the time it was written, America was just starting to undergo a shift in the standard models of business, and the sort of thinking it promoted revolutionized how a lot of people approached the idea of building their careers. So it's more like a supertrick that stopped being a supertrick because it was widely replicable.