Can you clarify your point? Crowded, poorly-ventilated wet markets like the Huanan Seafood Wholesale Market are quite different from American (or Chinese) supermarkets, and uncommon in the USA. American-style nursing homes are likewise uncommon in China, where it's more common for elderly parents to live with their children.

The conditions for a super-spreader event can arise in many different ways--before the contact tracers gave up, they found clusters in that wet market, those nursing homes, cruise ships, meat processors, migrant worker dormitories, and many other types of venues. I don't see why we'd ever expect the first cluster in the same type of venue in both countries, except by chance.