I really don’t think genetics have much to do with the current populations’ intelligence compared to many generations prior. There’s simply not been enough time evolutionarily speaking to make a difference I would say. Basically all of recorded history is a blip when considering evolution on a longer time scale.

Education and a stable, fruitful upbringing is what makes smart people if you ask me.

But I’m mostly basing this on a gut feeling or a hunch, not really anything rigorous.