I usually turn this question around: as a programmer, I'm responsible for a greater share of productivity than some people in different functions who are paid less. However, I do not work harder, do not sacrifice more, do not hate my job more - more likely the opposite, even. Why am I entitled to a larger share of profits than other people?
(I understand that the system generally "works better" this way. However, since we're talking about being entitled to something, I wonder if there's a moral argument that can be made.)