When self-hosting say Mastodon, you have to have a relationship with the hosting provider, the software developer, your users, and any other servers you federate with. This is more reminiscent of the network of relationships that dominated Feudal Europe.
Whereas, if you use Twitter, you basically have just a single, more comprehensive relationship to Twitter, which is closer to the central state model, where there is a central authority that subsumes and manages these relationships.
Also, in a feudal system, if you got robbed/assaulted there would be a very complicated means of trying to hold people responsible as there would be multiple domains and authorities involved. Similarly, fighting spam in a federated model is also complicated. Ina nation-state model, it’s much easier to at least try to impose a uniform standard of justice. Similarly, “Big Tech” can deal with spam much easier than federation.
Also, Apple’s App Store fees do not indicate feudalism. People in the modern world also pay various taxes to governments, even though we don’t have a feudal system.
So I think federation is more like feudalism and Big Tech is more analogous to the modern central government.