I agree completely with this argument as it remains focused on currency and banking thereof. But I think it's an overgeneralization to say that currency and consumer goods behave exactly the same way and have exactly the same durability. Yes, coins are just units of value and are understood to be equivalent to real goods of equal value- 3 dollars = $3 of bread. But while I agree that your historical examples of banking worked this way, I don't see that it eliminated the presence of price fixing of commodities by syndicates or of services by guilds. I can't think of a single moment in history where a small number of sufficiently small number large competitors didn't eventually align behind some measure of value fixing. Perhaps technology and historical circumstances change the algorithm of how much market share and how many actors are needed to create these circumstances, but they always seem to arise.