> > It's been shown to be strongly correlated with success in general

> Has it? I was under the impression we could hardly define, much less measure that.

IQ has a strong positive correlation with life outcomes. Economic and otherwise. Whether IQ is a good measure of "intelligence" remains debated but there's no question that high scores in that measure correlate with high scores in life outcome measures: Life expectancy, economic success, relationship success, etc. Every single thing you can measure about a person's life trends upwards with IQ.

Some (maybe much) of the effect can be attributed to privilege and other covariants, so we don't know if IQ is causal for life outcomes but we have strong evidence that it's correlated.

one study of many: https://www.scirp.org/journal/paperinformation?paperid=74943