IQ is only a slight predictor of individual of individual success there are many other factors that are superior to IQ for predicting individual success.
However the paradox is that while IQ is not a good predictor of individual success, the economic success of a country correlates heavily with the average IQ of the people in that country.
It is a paradox. One cannot simply say that IQ doesn't "predict" success. From the data, the answer seems much more complicated.
Sure, IQ “correlates strongly” with national economic success, but that’s because of other causal relationships, like that economic success predicts environmental conditions which are known contributors to IQ.
There’s no paradox here.
First off IQ only has a slight correlation with individual success past a certain point (someone with below 60 IQ is obviously going to have a hard time succeeding). The data shows that for high IQ and average IQ there is only a slight correlation with success.
Second what you said is patently false. We do not know if there is a causal relationship because a casual experiment is nearly impossible to conduct. This is very different from saying there is "no causal relationship." A correlation points to a possibility of causative relationships. Literally. You make a statement as if it was true, tell me the exact causal experiment you used to determine your statement about "no causal relationship".
Third. The correlation between economic success and IQ is much much stronger then the correlation between individual success and IQ.
Again there is a paradox. You are wrong.