That's not what zero-sum means. The definition of a zero sum "game" is simply one where the participants' payoffs (here, profits) sum to zero.
Nothing in the definition prevents some participants from being better players than others. As you noted above, some entities might also prefer to "buy" stability for their main operation instead of trying to minimize their spending on some of its inputs. Nevertheless, for every dollar made on futures, someone has lost (at least) that much. Except for the market-maker, the entire thing is a closed system. Thus, you'd expect the average return, across everyone trading the contract, to be zero, which is exactly what this paper shows.
The paper does show 47 people who turned a profit. Their analysis can't distinguish between rubes who haven't (yet) reverted to the mean and savvy traders with some kind of effective edge. It would be interesting to see what the loss distribution looks like.
Nothing in the definition prevents some participants from being better players than others. As you noted above, some entities might also prefer to "buy" stability for their main operation instead of trying to minimize their spending on some of its inputs. Nevertheless, for every dollar made on futures, someone has lost (at least) that much. Except for the market-maker, the entire thing is a closed system. Thus, you'd expect the average return, across everyone trading the contract, to be zero, which is exactly what this paper shows.
The paper does show 47 people who turned a profit. Their analysis can't distinguish between rubes who haven't (yet) reverted to the mean and savvy traders with some kind of effective edge. It would be interesting to see what the loss distribution looks like.