Nor did I ever claim that it was Zero Sum at any point. I just pointed out that there are, by necessity, always "losers". That doesn't make it a zero sum game, as the values can be different and have very confusing side effects.
Presumably what you're referring to is that in a realistic market, there are also tons of other people who are willing to swap their wares, and maybe they'll offer me something better for a gallon of water than a pound of meat. So sure, I could be taking a sub-optimal deal by trading with you at the rate you want. But the trade is still positive-sum, no loser in sight. In an efficient market most trade is net beneficial to everyone and doesn't necessarily have losers, including when you start layering in credit and derivatives and inflation and velocity of money and whatnot, even if it gets really complicated. That is possible because we all have slightly different self-valuations of money, goods, and risk at different scales, and the markets let you trade each for the other until you've self-optimized your portfolio blend.
That's not to say you can't come up with scenarios where there are unambiguous losers, but it's definitely not some law of economics or anything like that.
> it's definitely not some law of economics or anything like that.
This is a no true scotsman fallacy. It's true that this is not a preordained truth, but you'll realistically always have someone at a loss for as long as resources are limited. And if you can't see one than you're just ignoring the one's at a loss as irrelevant.
I.e. descendents with natural resources or even non-human entities in the context of meat production etc
Edit: I flatly reject the notion that strictly someone's gain requires someone's (non-proportinate) loss, ie that there are always "losers". That notion is also not really a current macroeconomic position.