Think about how logistics work, and how fuel has to be spent. You don’t want a decentralized network for physical goods. That’s extremely inefficient and wasteful.
Even if it’s just about the final point of sale… we kinda already have these aggregations of individual merchant stalls? We call them “malls” mostly, nowadays, or “markets”, depending on type. They exist, but keep in mind that a lot of stuff is centralized behind the scenes, be it maintenance, logistics or chains.