If so, there are other ways of looking at the same data that Cowen uses to determine, and then extrapolate, a trend of increasing inequality, http://cafehayek.com/2013/11/when-facts-arent-facts.html
Russ Roberts (the author of the above piece) also interviewed Tyler Cowen on EconTalk where they discussed the case of compensation to (book) writers, http://www.econtalk.org/archives/2013/09/tyler_cowen_on.html Cowen argues that superstars eat an ever larger share of the total compensation while Roberts notes that the average is being dragged down by the fact that there are few, if any, barriers to entry for new writers and writers who would have done well in the past (due to their talent, education, ability) still do well today.