Back when they started on that, we were worried they were going to kill ActivityPub like how Netscape got killed by IE durring the browser wars. EEE (Embrace, Expande, Eliminate), adopt the protocol, expand its capabilities while including propriatary portions of code, and lock the competition out when market saturation is achieved.

The issue is that fedivers residents are a bunch of tech-literate weirdos and called this bullshit the second the news dropped, and are 100% the type of people who make forks as soon as something like that would actually happen. Piefed being the perfect example, this part of the internet is perfectly fine just picking up their things and making something else (and we love it here for that).

Yep a lot of us built stuff like this before and will probably do it again.

piefed is working on it at the moment. I can see some stuff working. Following/posts that make it here/etc.. its coming along pretty quick!

Lemmy is all about groups. It doesn't have any way to connect to and interact with single users.

Mastodon, on the contrary, is all about single users following single users. It has no support for groups whatsoever. Mastodon users can follow Lemmy communities, yes. They can reply to posts, but in a very Mastodon way (automatic mentions, they'll probably insert hashtags etc.). Seeing (almost) the entire conversation is the default on Lemmy and extremely tedious and anything but straight-forward on Mastodon. And starting a new thread in a Lemmy community from Mastodon is difficult, nobody knows how to do it right, and whoever tries it will clash with Lemmy's culture.

Stuff like Friendica or Hubzilla is somewhat more general-purpose. It can do both. But I've yet to see a Lemmy user subscribe to a Friendica group or a Hubzilla forum (the opposite does work).

Also, Threads has introduced extremely strict rules for servers that want to federate.

Entire Fediverse server applications are incapable of following all these rules, either technologically or by concept.

For example, IIRC, Threads demanded a full public timeline. Hubzilla, (streams) and Forte do have that feature in code. But it's intentionally turned off server-wide by default, and there's a very good reason for this and for just about no serious admins of public servers ever turning it on.

First I've ever heard of Soundstorm, which apparently hasn't been updated in 7 years.

GitHub - weathermen/soundstorm: The Federated Social Audio Platform

The Federated Social Audio Platform. Contribute to weathermen/soundstorm development by creating an account on GitHub.

GitHub (github.com)

This kind of stuff is the coolest thing about the fediverse and ActivityPub to me.

All the things you mentioned are possible in theory but the tools and infrastructure to do it haven't been created.