Every business in the village has said what they need and what they've got spare. When one lines up with another, that's the supply chain recognising itself.
Think of a lost-and-found box crossed with a swap meet. One trader is missing a left glove. Another one has a spare left glove sitting in a drawer for years, assuming it's useless on its own. Put them in the same room and that drawer becomes valuable. Nobody had to manufacture anything new — the industry already had what it needed, it just didn't know where to look.
Scanning the directory for matches…