Carlos Perez claims: Douglas Adams said "Anything that is in the world when you’re born is normal and ordinary and is just a natural part of the way the world works." Now imagine children of today who have GPT-like systems always at their side. They will have IQs that will be off the scale!
If you're asking whether the next generation will be smarter than the current one, the answer is yes by virtue of the Flynn Effect.
If you're asking whether the subset of the next generation that uses GPTs heavily will be smarter than the subset of the next generation that doesn't, the answer is again yes, by virtue biased subset selection (the first group will be from richer countries with higher average IQs).
So regardless of the operationalization, the answer will probably be yes?
@jonsimon good take. yet, it is possible to stratify the population and get a more detail answer looking inside each group. I think that a similiar question that would be relevant for today is social networks, did they make people smarter?