not really. email and list serves are somewhat 'dead'. they are distributed in chunky dumps only every so many hours. bbses are closer to what engage people. conversations are updated in a more granular fashion with a greater respect for timeliness. the point i was making is the current existence of a turn-key box that could be the building block of a publicly administered peer to peer network. the power of peer pressure is not to be underestimated. even my son who is a software engineer, knowledgeable about android, hacks his pixel , etc is moving to an iPhone because he has many friends - not software savvy - who are all on iPhones and iMessage each other , FaceTime themselves, etc. The magic can happen with A box that you can turn on and simply click an 'install' button that gets a peer to peer chat app that runs in a sandbox, shares some of your NAS space, is always on - A hooli box to make a new internet
You're right on all your points. In detail, no less! Such a system could indeed be marvelous, a system to make a new internet for a new generation.
Yet, you're describing email still in essence. A system where people interact very rapidly in a distributed, authority-less magic box based network. Email happens to be chunk-y, though in practice it tends to be nearly as fast as chat.
But I'll humor you. Now you're describing XMPP. Magic sandboxed chat applications, peer-to-peer, NAS storage, authority-free, and monitization-free. Wrap it up in Docker or something, and you have your turnkey magic. Right? Right!
You still have all the problems that come with this. For example, stemming abuse is a major problem with decentralized systems. How do you stop spammers? Appeal to the decentralized community and hope? Peer pressure has never been enough to stop this. Authority and trust problems run rife. Most users are too ignorant and unskilled to look after their systems properly, which is a problem you won't be able to magic away.
I'm trying to be nice here. You're re-inventing email, in a way that does nothing to stem the basic problems of email. You have all the idealism that created email to begin with - lovely, beautiful, admirable idealism! - and little of the pragmatism.
Fundamentally, there have been two kinds of decentralized, authority-less, un-monetized networks: those that are unpopular and those that become popular enough to be subject to a ton of abuse. Abuse that leads to professional service offerings that re-centralize, re-intermediate, and re-monetize the services in order to make them usable to ordinary people again. It's absolutely possible that your idea would be neither of those! It's just that so far I've not been shown anything convincing that this could be the case.
It's also what email is.