The issue with e-commerce is mostly the same as that of social media, there are only a couple of platforms hence they can dictate everything for the users. So do you think the fediverse could also benefit e-commerce or could there be something resembling the fediverse but for e-commerce?
In theory yes and https://gitlab.com/bashrc2/epicyon has support for "sharing economy", but on a decentralized network fake reviews and product listings are potentially an even bigger problem.
I think we'll all be around to find out. Whether they end up federated with everyone else is up for debate, but the products still follow the eyeballs.
Advertisers especially are going to note how high engagement is compared to the other platforms, the rest will take care of itself eventually.