I said IQ by itself isn’t a good predictor. IQ is actually the best single predictor we have in the social sciences (not counting a person’s credit score; but that is an index of many underlying bits of information). But, by itself, IQ has low predictive power. Repeating myself, you want to use IQ in conjunction with something like conscientiousness to have a decent ability to predict. Alternately, use SAT and high school GPA in college admissions. The first measures potential and the second effort. You kind of disagree. Would you say what is the predictive power of IQ by itself.
No. I'm not so sure I disagree. Maybe somewhat agnostic on your other factors is a better description.
My point is in reference to the book and the conclusion they reached that there was a direct correlation between IQ and what I call societal achievements. The factors you mention were not addressed in the book, as best I recall.
While I fully agree that the factors you mention play a significant role, I have never seen a source that measures them across all societies. That's not to say they don't exist -- only that they are not broadly measured (e.g. SAT is used in less than half the countries in the world).
So, in my mind, I fall back to the book that concludes that there is a direct correlation between IQ and a society's achievements -- which makes it a predictor. To me, anecdotally this is relatively easy to confirm.