and, why is that?
It's extremely against company interests to federate.
it doesn't work irl, and if you don't understand that then keep asking this question in 10 years, or even 100 years.
>99% of people do.
Anything can be decentralized. But people will gravitate toward centralized solutions.
Email is only federated because it was used before it was commercialized. If companies could monopolize email they would. The solution here is government regulation requiring interconnection, like we got with phones and text messaging.