That being established, I.Q. is a simple dipstick that measures quantity. It doesn't indicate if or how much is used or how it is applied.
That assumes an equal amount of work. For those with high IQs who do not apply themselves, the results are not so stellar, and those with low IQ (often willing to take risks, perhaps because they do not understand the downside), hard work pays off, more often than not.
I must also note that those of us who have performed well on the tests are more likely to defend them.