Completely missing from the article are any references to differences between jobs with easily measurable output and those with difficult to measure value.
Software engineers and management are two great examples of professions where value is very difficult to measure. In the opinion of many, software engineers tend to be underpaid compared to the value they produce. Managers on the other hand, tend to be viewed as overpaid or at least better compensated compared to the value the produce. I believe that managers do a better job of capturing their value primarily because they (or someone just like them a step up the chain) hold the purse strings.
Back to what the article focuses on for a moment. Sure a superior producer might be able to capture more of their value than their low-producing counterpart. That's a drop in the bucket compared to C-level compensation vs salaryman pay.
In summation, people aren't upset that the guy in the next cubicle makes 20% more money because he's more productive. They're upset that the CEO makes 100x more than they do even in bad times for the company.