So-called "academic success" is based on a series of formal tests and rituals, just like IQ is. These tests could be useless as a metric of your knowledge, skills or abilities, just like you're arguing IQ is. Unfortunately, when the name of a performance indicator has the word "success" in it, you stop questioning the validity of such indicator, and you start using it as an absolute benchmark instead. This happens even though the trivial answer to "why do you go to school or college" is usually "for knowledge and skills", not "for academic success".
"Academic success" is required to enter many highly paid occupations: law, medicine, finance, etc. So I would disagree it is a useless indicator, it is directly related to one's future income.
I never said it is useless as an indicator of future income. I said it might be useless as an indicator of one's knowledge and skills, and knowledge and skills are what education is supposed to be about.
If you measure success by one's income, which is a good and clearly defined though still arbitrary indicator, I see no reason whatsoever to expect it would depend on IQ. People with high IQ are often less competitive and often question the need to maximize their income, which is obviously detrimental to such income.
