Isn't that basically what you'd expect with a progressive tax system? Paying taxes is not the only way to contribute to society -- almost all the money people earn do to some extent, through taxes, and consumption, and investments, etc. Which contributes more I don't know. That's why I was hoping for a citation.

To your second point, there is evidence that CEO performance is negatively related to their pay: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1572085. Measuring competence is difficult, wealth is a appealing proxy but maybe not that reliable.