Stock brokers are regularly getting beaten by monkeys when it comes to betting on the stock market, yet they are among the top earners in society. It's just insane to suggest that salaries are fair or that skill is in any way correlated to income.
Unless you believe that making lots of money proves that you are good at what you are doing, which makes the whole argument a tautology.
Edit: Also, the best work I've done is all open source. It isn't all very good stuff (far from it!), but it certainly is both more valuable and better than the corporate code I write for a living. Then there is http://www.ohloh.net/ that tries to estimate the labour costs of various open source projects. People have plowed thousands of hours of unpaid work into some of the highest regarded software projects on earth just for fun. They will never get properly compensated for their work. "From each according to his ability, to each according to his work." is the famous slogan of Socialism, but it certainly isn't how the world currently operates.