i think you may be mixing federated and small-web feel there. there exists the ability for individuals to have functioning email servers although it is difficult but fair considering how much of the world is reliant upon it and opposing it with various kinds of attacks. i dont thimk it requires many individuals to have their own servers for it to be considered federated, the fact that we have dozens of relatively big email providers to choose from who prioritize various different things is enough to cover the majority of peoples needs and i think that is the threshold requirement for a sufficient self sustaining federated network. regardless of that, if you compare this outcome of email as of present to lets just say a platform like discord whose goal is to facilitate messaging between people, you can evidently say thst emails outcome is better than the proprietary service that discord is locking people into and not making alternatives ways of accessing the service a simpler process.