The premise is supported by mountains of evidence that IQ (despite being a crude, one-dimensional measure of intelligence) is predictive of intellectual achievements and economic success, in individuals and populations.
So long as you don't look too close at the data. From the Flinn effect to the fact that IQ tests predict parenatal incomes mich better than future earnings the best thing you can say about the test is that it measures willingness to to arbitrary meaningless tasks for long periods of time. A very good predictor for success in most office jobs.