It seems the fediverse is continuing and growing again. Line go up is probably good!
https://fediverse.observer/stats&months=50
Total users are huge now.
There are many websites out there that pull data from the fediverse. So take that with a grain of salt. But anecdotally I am seeing a small rise in people using the various platforms as each get more mature and servers somewhat stabilize.
You make a lot of good points, and I think I agree with your overarching theme - we don't really know.
Piefed does a lot better job of not recommending the weird instances, and I do hope it overtakes Lemmy because ultimately Lemmy is built by a fringe group so they aren't going to stop recommending fringe groups.
I think that people are unlikely to keep using both Lemmy and Piefed long term. Piefed is new and exciting, in another year we should see people settling into an account and hopefully we'll have a better idea at whether the threadiverse is growing or shrinking.
PieFed, as per usual, offers more features than Lemmy, e.g. PieFed.zip places a user-level instance block upon those highly controversial instances (not Lemmy.ml though), but then tells users how to remove that block. This is an ideal scenario, not forcing users hands as defederation would but offering a real choice, as opt-in, to interact with them.
On the other hand, PieFed has a lot of problems that I think are going to preclude a lot of people on Reddit from being excited about it. Most of the criticism has ended up being proven as disinformation... but not all. For instance, the aforementioned user-level blocks end up shadow-banning users without any acknowledgement to them that their content is not being received. That is somewhat Lemmy's fault for not being able to handle such blocks, but in any case PieFed decided to go ahead and do it regardless - which I support that choice btw - but then it does leave PieFed open to a criticism that it implements shadow-banning procedures. Which Lemmy does not, but at the cost of simply doing nothing at all about the situation.
And now PieFed is expanding upon that practice to shadow-censor votes coming in, even from Lemmy or Mbin instances, whenever the user exceeds a daily vote quota. Which is nowhere explained to the users whose votes are being discarded. I've heard multiple communities canceling their plans to migrate from their current location on a Lemmy instance to a PieFed one over this issue. Note that it is theoretically possible for an instance admin to change this behavior - but it is opt-out, not opt-in, and it was barely announced at all, leaving many admins surprised at the new behavior occuring on their machines, plus it went against strong community push-back, citing logic that I think I've only heard one person say that they understood and agreed with.
The primary criticisms of the Threadiverse are lack of content overall and the fact that it is too confusing for people's tastes. PieFed has made MAJOR strides in making things simpler for people, but as I have described above, it is also making things even more complicated in some other ways. And the crux of it seems to be: PieFed wants to become more like Mastodon, a place for "serious discussions", not a place for social media like with memes and where people upvote content in order to make people feel good emotionally. Which, if true, would be 100% fine btw, except that it claims to be the opposite, hence muddying the issue enormously, forcing users to discern the real truth particularly when it is in direct contradiction to the words they are told about it. i.e., this place is too confusing for people to want to figure us out - it is far too much effort, for very little gain, compared to them simply remaining on Reddit, no matter how enshittified it becomes.