Yes, the .85 is probably at the upper end of the estimate. The genetic studies are the conceivable floor.

I'm not sure what you mean by "hereditarian" given that even the genetic studies obviously point to significant heritability.

This is always a funny conversation because on the one side you have people saying "intelligence is both heritable and correlated with nearly every outcome we care about."

On the other hand you have people saying "nuh uh! It's only... medium-high heritability and medium-high correlation with other positive outcomes," as if it makes any material difference to any downstream question.