Earlier quoted context omitted.
Nobel winner James Heckman did a lot of work on this [1]. The takeaway is that IQ doesn't matter as much as other attributes (character, learned skills, etc.) in life outcomes. HN style crows way overvalue IQ style skills when intelligence has multiple dimensions, many of which matter more than IQ. IQ is effectively just a measure of test-taking skills. That's useful in some areas, but you could see someone like Geng…
IQ is a fair predictor of achievement in life, though. But there are other predictors too, such as parents' socio-economic status, or geographical location. We wouldn't claim these things measure intelligence, though. IQ is a proxy for intelligence, but one with great shortcomings. Unfortunately, there's no agreed upon definition of intelligence, let alone an operalization, and a way of measuring it. So IQ keeps bein…
Uhuh.... so this line it's crazy, right?
It's really strange you concede that we have no theory and hence no way of verifying whether an IQ score is a valid and reliable measure of the thing we have no theory of... and yet, you say it is a "proxy for intelligence"
The entire edifice of research which makes these claims is a product of a pseudoscientific use of statistics by amateur statisticians. The vast majority of the results you think exist in the literature are frauds, and often egregious ones at that.
A human being is one of the most complex systems known to exist in nature, and the frauds in psychometrics are very far away from being up to the task of studying them. The greatest minds in applied sciences, matehmatics and statistics would largely throw up their hands at the job of measuring "intelligence" --- that some fools havent, is no good thing.