>>2292622until Marx mainstream economic theory, called classical economics, defended a variety of labor theories of value, that differed mostly in detail, but the essential gist of it was that the cost of production was the primary (or most influential) factor in the formation of a commodity's
natural (or equilibrium) price, which is its
normal price under
normal circumstances, and also, that the primary (or most influential) factor in the cost of production was contribution of labor. Marx took classical economics, drew the obvious conclusions of class struggle, exploitation, alienation, and revolution from it, resolved the remaining contradictions of classical economics, and attacked the mode of production as a transitory historical form rather than an eternal fixture (by drawing from history, anthropology, and science, rather than simply economics). Marx is the Darwin of economics. For this reason mainstream economics transformed from a progressive scientific investigation into wages profit and rent (under the classicals) into a priesthood defending the mode of production from revolutionary movement under the economists who came after Marx. Marx killed political economy with his critique, and the bourgeoisie has been parading around its dead corpse, and giving it papal authority, and decorating it with silly innovations like Marginal Utility Theory, and Subjective Theory of Value.
To the extent that there can be a critique of Marx from the Communists themselves, it simply tries to build upon and refine the specifics of Marx's discoveries, rather than refute the essence of them
(see vid related regarding the bees/architect passage from volume 1 for an example). This is very similar to how biologists build upon and refine Darwin rather than refuting the essence of him. Only clowns try to say evolution is wrong. Only clowns try to say Marx is wrong.