Why do we often implicitly consider the human cognitive capability as it is embodied in adult individuals' biological makeup to be immutable, now and in the fut

Why do we often implicitly consider the human cognitive capability as it is embodied in adult individuals' biological makeup to be immutable, now and in the future? Even a single existence proof of a method for cognitive enhancement would deal away with this frame. I get that we aren't (yet) spoiled by availability of (gene or cellular) therapies uplifting our IQs, but hey, at least those mice were able to receive theirs: https://www.cell.com/cell-stem-cell/pdf/S1934-5909(13)00007-6.pdf https://www.cell.com/cell-stem-cell/pdf/S1934-5909(13)00007-... Given the sheer amount of capital available for trial and error on (sometimes ridiculous like juicero) consumer products it's weird that so little of it is allocated to advance the biotechnology of human enhancement.