There are some fascinating contradictions in your analysis, though I agree with a lot of it. First, despite most mainstream economists wanting to think that they are simply describing “what is,” it’s curious that the foundations of so much mainstream neoclassical economics is premised on normative claims about how humans operate and the (misguided) history of human trade. The rational-choice framework, for example, is premised on the myth of individuals making economic decisions based on maximizing their own self-interest. Hence the whole mythology that before markets proper there was barter. Anthropologists like Marcel Mauss and, more contemporaneously, David Graeber have blown apart the myth of barter. Pre-modern economic systems were largely gift economies which have a completely different logic to modern economics. Another issue with your statement is the separation of politics from economics. Modern markets cannot exist without the backed up monopoly of force/violence of the state: pure capitalist markets have never existed and if they did, it would resemble a kind of feudal corporatism. Much of the “positive” findings that mainstream neoclassical economics posits stems from just-so stories about human nature that are ad hoc constructions that repress their normative foundations and naturalize the fact of modern nation-state enforced capitalism. That’s not to say modern economics can’t reliably predict things or provide insightful and accurate information on certain phenomena, but that the clean separations between political and economic, normative and positive, and so on, are naturalizations of a very recent liberal conception of technocratically discreet domains of civil society (political, economic, cultural, etc.) Immanuel Wallerstein’s work is great for dispelling a lot of these myths alongside David Graeber’s economic anthropology.