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.