It's not a theory it's a fact. If a male was useless at hunting and was nothing but a burden he'd be kicked out of the tribe and because he would then be an outcast he would no longer have access to the opposite sex and would not be able to pass on his inferior genes to another generation.
On the other hand the tribal chief, the alpha male, would fuck many women and spread his seed far and wide.
That is why the human species thrived and prospered.
We now have the opposite scenario where the loses of society are allowed to breed like flies (in fact they are paid to breed by a generous welfare system) and the alpha males end up in prison for being sexual predators.
No prizes for guessing where we are headed.