It works in communities, not corporations. Every federation seems to die when enough millions are connected to it. Facebook used xmpp for chat. Google chat could federate too. Apple promised iMessage and then hid behind a silly excuse.

It's extremely against company interests to federate.

ever realized that its only incompetent people who could never build a product (what problem are you solving?) who ask for silly things like this?

it doesn't work irl, and if you don't understand that then keep asking this question in 10 years, or even 100 years.

email works, not everything has to be run by corporate greed

Do you use Gmail, outlook, etc? A provider backed by 1T+ worth companies?

>99% of people do.

Anything can be decentralized. But people will gravitate toward centralized solutions.

That has nothing to do with federation. A Gmail user can talk to an Outlook user. A Slack user cannot talk to a Teams user.

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.