Ken Griffin vs John D Rockefeller

I'm not sure what to make of Andrew Samwick's defense of Kenneth Griffin, against the deprecations of Paul Krugman. Krugman's point is that Griffin makes more, as a multiple of average earnings, than even John D Rockefeller made in 1894. Samwick's defense is that Griffin is not a monopolist, and is "confident, contrarian, and accurate". He concludes:

I spend a lot of time around college students. I spend a lot of my energy trying to get them to display those three characteristics. Krugman seems to think that one "Kenneth Griffin" is overvalued at 4.5 "John D. Rockefellers." On the contrary, I think it's a buy.

I'm not sure that Krugman considers Griffin overvalued, per se. It's just that if you're making over a billion dollars a year, you can certainly afford to pay more in the way of taxes than someone scraping by on a few hundred thousand. In reality, however, Griffin pays less in taxes than the upper-middle classes, not more. In other words, the question isn't how smart or valuable Griffin is – it's whether society has any interest in him keeping more of his income than people much poorer than himself.

I'd also like to point out that if you compare the net worth of Griffin and Rockefeller, I daresay that Rockefeller would still come out comfortably on top. Income is a lot, but it isn't everything.