> In many cases it isn't being replaced by anything similar.
Which is more or less what you'd expect; that's what normally happens to dying social networks. Most people leaving LiveJournal didn't go to Dreamwidth or similar (ie Livejournal clones); they went to Twitter or Tumblr or other not particularly LiveJournal-like things. I think it's actually fairly plausible now that Threads acts as a drop-in replacement for Twitter, but it's also plausible that it's Twitter's Dreamwidth, and most users go to different sorts of social networks entirely.
Which is more or less what you'd expect; that's what normally happens to dying social networks. Most people leaving LiveJournal didn't go to Dreamwidth or similar (ie Livejournal clones); they went to Twitter or Tumblr or other not particularly LiveJournal-like things. I think it's actually fairly plausible now that Threads acts as a drop-in replacement for Twitter, but it's also plausible that it's Twitter's Dreamwidth, and most users go to different sorts of social networks entirely.