> So, what’s the difference between a “wet market” and the sort of familiar farmer’s market of butchers/fishmongers/etc. that five-star restaurants source from all over the world?

That's exactly the question I have. How are these Chinese markets fundamentally different from, say, the Japanese Tsukiji fish market? Taking a look at pictures like https://commons.m.wikimedia.org/wiki/File:Vendors_begin_sell... it doesn't strike me as very much different from the Chinese wet markets.