I'm still here! I'm more interested in learning from your perspectives than dumping mine.
Edit: so I failed a Perception check and read this as being about this community. I am very much not on Reddit anymore.
If I had to guess, the Redditors "lost" probably diffused into several Lemmy communities, Raddle, several Mastodon instances, several Discord servers, and several places unknown to us. Some of us probably took the lack of activity in each individual forum as a lack of interest. We fragmented. I know you're in a bunch of anarchist communities, and I'm subscribed to a few, but there's probably some people we're missing.