Explain why high wages and big bonuses

One contributor to the New York Times comments section writes, " There are sure to be lots of pointed, angry posts about how unfair it is that these guys make so much money etc. But if we are honest, there is a fair amount of envy and pure remorse that we weren’t bright enough to go down that path! And these guys are very bright." How could these comments be construed to explain why high wages and big bonuses are used by Goldman to motivate its workers? What is it that makes big money (or the possibility of big money) function as a powerful motivator to encourage employees to work hard and well? Ethically, how can this use of big money be justified?