We don't want "are you rich, do you smoke" because the selection effect (we are rich because we were born upper middle class, and we're not powerful because powerful people have better things to do than explore the internet until they land on odd forums).

Otherwise the value of an idea is judged by the types of people who happen to stumble upon them.

What we want is "After being exposed to the ideas, did you get richer", "did you quite smoking", etc. Before after.

why aren't they leveraging their high IQs

IQ is just another selection effect confound to control for. Priors say there is absolutely no way rationality training will alter your IQ (and besides the IQ data is mostly from standardized test scores taken in high school anyhow) If high IQ people land up here that just means high IQ people crawl the internet more and stick around more.