So, I'll summarize how does patriarchy, male disposability and marxist modes of production interact in pre-gender-studies anthropology. This is seriously studied and you can search up what I'm going to say.

First of all, primates -most mammals do NOT- are organized in small fusion-fission bands with alpha males controlling the group (even in the more gender-egalitarian bonobos!!).

But as portrained by Dunbar, the evolution of language had the specific evolutionary advantage of create coalitions between females and beta males through gossiping and boasting-shaming against alpha males (who tried to gain power and influence through high quality hunting). In this way, survival of each individual is tied to the survival of the group.

Edit: don't call it "alphas" and "betas", whatever. Those are nonscientific terminology. What is s fact is that hierarchies are constantly being created inside bands and that these are systemstically dismantled through forced sharing and boasting shaming, which is considered the evolutive advantage of language (which creates alliances amongst people who do not have power that counteract those who are trying to gain power). Yes, in the literature, those who would have power are usually considered to be men and they are usually trying to gain legitimacy through hunting. By forcing them to share, they are unable to accumulate power that way.

Edit2: this is not my main point. Please stop focusing on these two paragraphs, my main point is kin corporate mode of production, how it works and why it leads to male disposability and other things!!!

This implies that extremely early human societies (Original Affluent Societies) are all egalitarian. Not just egalitarian, but fiercely egalitarian as portraid by Sahlins.

Patriarchy is a real anthropological structure heavily studied since XIX century. Just assuming that it doesn't exist isn't scientifical. But what patriarchy really means is more nuanced that college students seem to describe.

So, in early societies, goods flow through gift-giving along the lines of kinship. That is, you give gifts to your brother-in-law.

But because there is no division of labour in early communal societies, this gift-giving "commerce" does not create inequalities.

It all starts with division of labour and private propierty, as studied by Binford. So, what happens is that different people get access to different resources (say, some people live near a river so they get fish and other near a forest and they get hids), and that implies that each band needs each other for their own survival, creating interlinked groups of hundreds of individuals. But it also means some groups get access to high quality resources. So this access means life and death and warfare will emerge from it.

This is the context where kin corporate mode of production (commonly known as "tribalism", and linked to "patriarchy" starts to emmerge), as studied by Eric Wolf and Karen Sacks.

So, how does kin corporate mode of production works and why does it create patriarchy and male disposability?

Because resources flow through kinship and because of the constant warfare, marriage alliances need to be carefully planned since they sustain the social and economic structure.

This implies arranged marriage -think something like Game of Thrones' Tiwyn Lannister-. Parents get to control their children lives, since they have to decide what will be best for the survival of the family. Rules of marriage and inheritance are contrived and very strict. Children do not have any choice about who to fall in love with.

Extramarital sex gets the same punishment than rape since in both cases it is damaging the delicate network of alliances, made for economy and for warfare. When a rape or an extramarital sex ensues, warfare by the damaged clan starts, which creates a feud (warfare because of revenge) that takes centuries and dozens of generations to stop. It usually stops through a new marriage alliance.

(Continuation in comments)