Poking around on Wikipedia regarding this, I found this quote from Engles on the Surplue Value page:
“Whence comes this surplus-value? It cannot come either from the buyer buying the commodities under their value, or from the seller selling them above their value. For in both cases the gains and the losses of each individual cancel each other, as each individual is in turn buyer and seller. Nor can it come from cheating, for though cheating can enrich one person at the expense of another, it cannot increase the total sum possessed by both, and therefore cannot augment the sum of the values in circulation. (…) This problem must be solved, and it must be solved in a purely economic way, excluding all cheating and the intervention of any force — the problem being: how is it possible constantly to sell dearer than one has bought, even on the hypothesis that equal values are always exchanged for equal values?” "
The bolded part is one of the big problems with the LTV. The idea is that exchanges occur when values are equal, rather than the marginalist/subjective view where exchanges occur when both parties value the other’s goods more highly than the seller. This is, I believe, why so many of Marx’s criticis focus on his lack of attention paid to time, and how it affects the utility, and therefore prices. Since, for Marx, exhange is a zero-sum game, if one party is to prosper, it is at the expense of the other, rather than a mutally beneficial exchange.
In reality, due to marginal utility, wants, needs, etc, every successful trade increases the overal “psychic profit” (as Rothbard puts it in MES) of the system. Marxism, to my knowledge, doesn’t address this, which is why they balk at the idea that a worker can “benefit” from being paid in wages now rather than waiting to sell the “full product” later, if they did all the work themselves and accumulated thier own capital. Once they see that they’re wrong about the possibility of a mutually beneficial exchange in the form of wage labor, they must fall back on the “worker doesn’t have access to capital” argument. Of course, since in a free society any worker, through savings, can accumulate his own capital, they then attack the ownership of capital in the present. Because the capitalist uses force to restrain the worker from using his machines, he is put in an advantagous position to demand a raw deal from the worker. This is the heart, I believe, of the Marxist criticism of capitalism, and ties back into the Capitalism/Feudalism stuff that started off this thread.
Notice though that we have totally demolished the idea that it’s wage-labor that they claim actually causes the “problem”. It’s devolved into a dissagreement over property rights and ethics/morality. In my limited understanding, this basically throws Marx’s whole crisis theory out the window.