I think that what is fundamental to understand is that the State defines the laws that govern property rights. There is a lot of minute detail that goes into this. For example, the State defines what happens to property after someone dies (their estate), what kinds of property there are, how various forms of property can be taxed, etc. If you take land law, for instance... usually the Sovereign State is the only entity with absolute property rights to land. Everyone and everything else (think, Banks) is merely granted certain, tiered rights by the State.
Ok, so capitalism isn't defined the same way by everyone. Some people (especially its most vocal advocates) define it by the prevalence of market exchanges. Some people define it by the private ownership of the means of production and a class society that encourages propertyless citizens to sell their labor power for wages. Et cetra. One way or another, it's the State that writes the rules of economy by dictating rights to property. Significantly, one of the things that the State does to make capitalism possible is that it sets the legal foundation for a market in labor power... the right of someone to buy and sell your time, to hire and fire you, and at what rate of pay. Not a market in laborers, which was what slavery was. But a market in labor power. The State also backs a national currency that facilitates such a market.
Additionally, by defining the rights to industrial technology the way that most states have... as something that can be bought and sold in the market ...states make it possible for the centralized control of such technology in the private hands of various people and institutions. The important thing here is that the State could just as well define the rights to said industrial technology in other ways. They could make industrial technology a form of property that only the Sovereign State has rights to, as they do with some forms of land and other forms of property. Socialists are for this "Nationalization" of the means of production. They basically want the State to make industrial technology a utility governed however the state they're citizens of is governed.
Anyway... the answer to your question is that it's difficult to imagine stateless peoples regulating their relationships to property in such a way that they would produce a form of capitalism. It's very much an economic technique that states use to accumulate wealth (and power) for themselves. Now that the Cold War is over, this isn't such an obvious point. However, the underlying argument you'll get from most Cold War-era anti-communists are exactly about how much wealthier those states are that use capitalism than those that nationalized the means of production. It's also evident that capitalism is a technique of the State when you look at imperialism, or the globalization of trade, or the history of primitive accumulation. Capitalism is really good at motivating citizens to compete with each other to produce more wealth for the State ...the State, who taxes them.
I like to keep in mind that I'm not a Socialist because my fight against capitalism isn't just a fight against the laws that the State protects governing the relevant properties of capitalist systems. My fight against capitalism isn't a fight for the State to pass new laws that remove some property from the private sector and make it a national utility. As an anarchist, my fight against capitalism is just one aspect of a fight against the existence of the State.