Of course, I completely agree (as I wrote on page 1). The "average Joe the Plumber" income might actually be lower than in Europe because of income disparity.
However, the effect doesn't really seem to reverse the ranking. Wikipedia* has a ranking based on the median income. The differences lessen, but the U. S. still sits at number 1.
http://en.wikipedia.org/wiki/Househo..._.28PPP.29_.24
Maybe, there are factors not or not correctly considered in these statitics, e. g. health care might have been forgotten (although I doubt that). At least in the media, surviving on an average in the U. S. is apparently seen as surprisingly difficult, but that might be a perceived difficulty. Living in a rented apartment, driving a compact car and so on seems to be better accepted in Europe than in the U. S., so the income and costs might be the same or even better, but the expectation of what one should earn might be different. That alone could still, of course, lead to less enthusiasm in paying MMO fees.
*Yes, yes, it's Wikipedia, where theoretically, any idiot can post bullsh1t data, I know, I know. But it's a discussion on an MMO messageboard, not a dissertation.