If you’re taking a materialist approach, you would recognize that hierarchy was more effective than primitive communism, not Anarchism. You’d have to argue against modern propositions of flat organization, not just anarcho-primitivism. I’m sure many Anarchists would agree with you that hierarchical forms of structure are generally more effective than Anarcho-Primitivism, but would disagree that hierarchy is necessary or even better than modern Anarchist theory.
I’m well aware of Marx’s rejections of Anarchism, I just think that since Marx is a human and could not predict modern Anarchist theory, modern Marxists should argue against modern Anarchism, rather than historical.