@Npars01 risk is probably that this evoles as e-mail has. Officially has always been a bunch of open protocols, but nowadays it is mostly a oligopoly (with Google Mail and Microsoft Exchange/Outlook as the dominant platforms) and it is very difficult to run your own server due to all extensions "against spam and scams" (meaning that most of your mails are going to silently be filtered without even ending in the Spam folder).
I hope the Fediverse better resists such EEE.