@thenexusofprivacy So, I've just kinda got a stream of random tidbits here that'll hopefully sorta surmise my thoughts.

The good:

First off, it's shrunk but it's by no means dead. Things grow and shrink and grow again, if it was a straight line with no variation I'd assume it was fake.

Also, Mastodon is not all of activity pub. Threads has brought a lot if people onto the protocol, and while it's still in development it seems to be intended to work interoperably and the devs said they plan to let people migrate out and take their following/followers with them. I expect this to really supercharge the ecosystem.

The indifferent:

This isn't 2020 anymore, and there's more protocols out there. Nostr, in my opinion, is leagues better in the decentralization and user options/customizations department. AT (Bluesky) is leagues better in the end user was of use department. Both of those protocols are also much, much, lighter to host.

Activity pub also has it's advantages of course. Being the oldest and also being great for communities are two quite big ones.

Some people have chosen to either leave Activity Pub for those protocols, or joined the decentralized ecosystem directly into one of the other two. It's indifferent, though, because it's a decentralized ecosystem. All three can chat with each other, so Mastodon & Activity Pub may have shrunk - but the amount of people you can communicate with on them has risen exponentially thanks to bridges.

The ugly:

Federation is a mess. You can have a dozen friends on Activity Pub, a dozen on other protocols connected via bridges or threads and find you can only talk to two or three. That's a problem; most would give up before understanding why, and many more would likely figure out why and the decide it's not worth their time working around. After the Bluesky wave I've heard Mastodon be called some variation of "bickering fiefs" a couple dozen times.

There's also some toxicity within the space. Most people I've interacted with have been great, but it still rears it's head now and then. You can get nearly bullied off the platform if you suggest people be nice to Windows users. It was kinda funny to see that blog post shortly after I jokingly said "you guys would probably put a hit out on me if I said I was using Windows" in a similar thread. In a similar vein, while accessibility is great, I'd bet more people have left the protocol after being yelled at for not using alt text then there are users who rely on alt text.

My predictions:

I'd bet that all three protocols grow a lot in the future and that more platforms start integrating one or more of the three big protocols. It's a cheat code for new platforms to automatically have a bunch of content, and it's free platform software already built. Federation issues and fediverse specific toxicity issues will potentially be eternal septembered away. Most people won't care what OS you use and will want to be able to talk to their friends as apposed to having current federation. There might be a small splinter group of the older crowd using opt-in federation, but most of the ecosystem will change if it grows.

I'd also bet the three big protocols will continue to get closer. All three can already communicate, and heck, I, as an incompitant programmer, made a quick script that lets any Nostr client communicate with Mastodon &/or Bluesky. Throw some compitant devs at it and soon enough you probably won't even be able to tell at first glance what protocol the other person you're communicating with is on. Bluesky and Nostr in the mix bring Mastodon's ~800k monthly active users to like ~15 million. A more connected ecosystem make things better for everyone.