Virginia Postrel says:

This sort of indirect genetic evidence for human evolution is going to pile up until it resembles the overwhelming geological case against believing the earth is a few thousand years old.

Maybe so. But to say so is an act of faith.

Is there a competing scientific theory (ie that does not involve creation of humans as they are) for how human brains got to be the way they are? Not that I know of. But that is not the same as saying the current theory is correct. It might be telling us more about the ingenuity of the practitioners in the field in creating alternative explanations.