IQ is the measurement of how capable you are at abstract learning. So a lower IQ will lock you out of certain jobs, at least on merit alone. Like you won't be a university math professor with a 110 IQ, but you'd probably be a fine nurse. A 75 IQ locks you out of basically any job. I believe the military found that ~83 is the lowest IQ that is trainable for the most rudimentary job.
But having a high IQ is in-and-of-itself, not a guarantee of success, because socio-economic factors can also lock you out of certain jobs. 100 years ago, being a woman was enough to prevent you from being a university professor, regardless of your IQ. And even today, you still have to be born in the right country to the right parents to have the chance to be a doctor or something.
However, there is a pretty big difference between a 110IQ and a 125. That's a 1.5 standard deviation improvement. That's like comparing an American man who is 6'1 to one who is 6'6.
This seems to hint no: https://medium.com/incerto/iq-is-largely-a-pseudoscientific-...
https://www.jstor.org/stable/20628656?seq=1
~125 eases entry into well-paid middle class jobs. Over 140 people start to seem weird by median standards. Over 160 they can seem very weird indeed, and are likely to become isolated without a compatible environment. So they're just as likely to fail spectacularly as to become innovative successes.
So basically IQ "works" in the lower range, and this shows through as a weaker correlation across the entire range, even though it is meaningless in the upper range.
This would then make sense too -- in the low end, IQ is affected by things like malnutrition, lead poisoning, and the like, which happen to people who live in areas where everyone are having worse life outcomes, but not because of their IQ.
I wish I had a reference for this hypothesis but I lost it. if someone does please hit me up.