I disagree with that. Maybe as you get up to 'pretty smart' sure but once you hit 'high' IQ, these people can struggle with society. Yet another reason metal has alot of the smartypantses. On top of that the upper/middle class has some shocking parental priorities! Based on the following of money/career...
Basically, I just can't generalise like that
If you put back the stuff you removed from my quote...
it's an easy enough argument to say that the more wealthy a person is, the smarter they are/higher their IQ will be (assuming that IQ is an accurate test of intelligence to begin with).
Obviously, there are exceptions to the rules, and you get totally inept engineers and stuff who are great with machines but suck with humans - fair enough. There's a point of diminishing returns with IQ, of course.
Metalheads being "smartypanses" is a completely different issue.
You say you "just can't generalise like that," but you go on to say that middle/upper class people have "some shocking parental priorities"?? I'm not going to say they always make the best parents, but there are shitty parents in all socioeconomic brackets.
I don't care what kind of exceptions to the rules you can find - wealthy people are, by and large, smarter and more intelligent than poor people. Without getting into any other obvious reason as to why this is true - just think about it. Anyone remotely intelligent is going to find a way to money. If they lack skills, they'll find a way around it. If they lack qualifications, they'll find a way to get them or to work without them. Stupid people will just lack those skills and qualifications and not make as much money.
It's worth noting with this study that correlation does NOT necessarily equal causation; just because people with higher IQ's are liberal, atheist, and monogamist does not mean that being liberal, atheist, and monogamist makes you smarter, or that being smarter makes you more liberal, atheist, or monogamist.