Thank you for your disagreement. I would like to point out that your disagreement does not in any remote way make my statement any less (or any more) factual.

I don't know why you assume the claim is unsubstantiated. I think it makes a lot of sense that people with lower IQs will have a lot of trouble in life.

Maybe it's not due to bad work ethic but merely due to them not having the cognitive ability to function properly in society in such a way that allows for the positive exchange of value.

I maintain that people with low IQ have this problem that makes it incredibly difficult for them to climb out of poverty, and I think this claim is very much substantiated, but I am not a scientist so I cannot back this up, but I have heard it on multiple occasions from people who I consider authorities on the subject.