Price fixing affects the whole economy. Beef farmers in the US have to produce more because there is a greater demand, but the demand side benefits because they can buy the milk at a lower price. Price fixing also prevents farmers from exploring alternatives and expanding into new markets. The market price is the fair price. Canadian farmers may get "fair pay" for their milk, but they don't end up selling nearly as much. The economy as a whole pays the price, from the farmers to the fishermen. And deferring costs can often lead to prohibitive logistical issues and debt.

Price fixing is downright criminal collusion. Also, commodity coins may be in use currently—but once people realize they don't service an actual purpose (apart from complicating ledgers), they will be abandoned. Speculation is keeping them afloat.