My understanding is that’s way at the upper end and there are other reputable studies (which you can search for) that put it down around 50% in twin studies, which doesn’t necessarily mean you’re going to be smart just because your parents are. But that’s irrelevant. The question being asked was: if IQ is genetic, why do we need teaching? This is like asking why you’d need ever need gas if you had extra-large fuel tank installed in your car.