The claim is that Jews apparently developed this super intelligence in a matter of several hundred years, at a time when natural selection no longer eliminated whole population groups that were unfit or lacking in certain abilities vital to thriving in their environment. This happened at a time when Jews were moving into areas that already had established societies and economies that didnt require anything be built or created from scratch. They apparently just became super smart in this short amount of time because the talmud required them to be literate and wealthy Jews had more kids(something which wouldn't be exclusive to Jews, and which doesn't seem to be the case in the pale of settlement and other areas where their population exploded despite being full of poverty and dysfunction). They didn't have a strict eugenics regimen, they just somehow kind of magically become so much smarter through higher rates of literacy and the success of some of them in certain niche areas that required literacy and the ability to charge interest-which was outlawed for christians.

This doesn't seem like it would create much of a lasting intelligence gap in such a short amount of time, and at the very least would only select for SOME cognitive abilities, while other vital abilities could atrophy or be rendered irrelevant because of the niche roles they filled in these societies.

You also keep repeating the claim that Jews have this substantially higher overall IQ when that very notion is questionable. Certainly SOME groups of Jews scored above average on IQ tests, but that proves absolutely nothing aside from the fact SOME Jews have above average verbal intelligence, which I don't think anyone denies. One could point out that Jews were also alleged to be feeble minded based on intelligent tests of immigrants and army recruits. So cherry picking isolated small IQ samples doesn't prove anything.