I don’t think the “decentralize and federate everything” strategy is a good idea when it comes to online marketplaces.
We’ve seen how quickly bad actors can wreak havoc on the Fediverse like that one time when Lemmy Shitpost was closed for weeks due to people creating new instances of their own and spamming the community with CSAM. Imagine how much you open the community up to scams or criminal activity when money gets involved.
Everyone would likely defederate from them, much in the same way that you all rushed to close the shutters upon Threads.
I also don’t ever see this happening, unless Spez fucks up with Reddit so badly that it sparks a mass user exodus, much in the same way that Digg v4 sank any hopes of Kevin Rose remaining a successful tech entrepreneur.