Without reading the thread I would assume the average IQ here is way above average just by the fact that this group is predominately engineers, doctors, lawyers, business owners, and other types of high-paid professionals. You don't end up with those job titles or credentials by being average intelligence.
The whole point of that IQ thread was to highlight the apparent (but false) correlation between IQ and income.
I think we all like to believe that if you are paid an above-average wage, it is because you are of above average IQ. At least those of us who are paid an above-average wage like to believe it.
And in the middle third of the IQ or income spectrum, I might believe there is at least weak correlation. But if you spend any time out at the fringe of either one, you'll quickly convince yourself the relationship doesn't hold. Some of the richest people I know aren't very bright. Some of the smartest people I know aren't very rich.
Americans in particular tend to assess value in terms of the almighty dollars, as if a price tag was the ultimate arbiter of quality. By that metric a GMC Yukon is a better car than a Chevy Tahoe because it costs thousands more, even though they are identical vehicles manufactured in the same factory by the same workers. This mistake is deliberately planted in us by marketers, and it partly explains why we like to think that some people, like some cars, are better than others just because they cost more.
Snap out of it, people! Learn to judge things, and people, on the metrics that you decide are important. The guy running the soup kitchen does more good for the world than the guy running the hedge fund, despite the thousand fold difference in paycheck. Isn't that worth something?