Introverts vs Extroverts?

In the article, Is There an Optimal Poker Personality Profile?, Dan Mezick explores which of the 16 Meyer Briggs personality types might be good at poker. I found this observation interesting.

[I]t is well known that chess masters are often introverts. Yet the world chess champion does not win five million dollars in cash, as did the World Series of Poker Champion in 2004. The history of chess is not uniquely American, as is poker. As we all know, American society richly rewards total extroverts. The idea that introverts somehow have an big advantage in a uniquely American (and intensely competitive) game like poker has got to have a positive effect on how introverts are perceived worldwide.

Research into poker personality would likely start with a study of the current population of known long-run champions in tournament and cash games. I strongly suspect that the majority of current poker champions have the 'INTP' or 'INTJ' personality types.

INTP is short for 'Introverted iNtuitive Thinking Perceiving', and INTJ is short for 'Introverted iNtuitive Thinking Judging'. My best guess is that the INTJ type is probably the most predisposed to poker, because this type is motivated by the practical application of knowledge more so than the INTP....

Perhaps 70, 75 or even 80% of all poker champions are of these two types. If this was an verified scientific fact, what might that mean for poker worldwide? Perhaps a correct but inverse conclusion could be correctly drawn. Perhaps some specific Myers-Briggs personality types are more apt to perform poorly at poker, in the same way a narrow subset of personality types is apt to do very well.