Number of (active) Lemmy users seems to stabilize and I think this is a great thing. Indeed we got a lot of users when reddit shutdown its API (I was among them despite being a long time oss user), many have left, but the community seems now to stabilize to ~ ½ of the big grow in june '23. I think this is very nice for lemmy, we can be proud of this project.
The stats come from: https://fedidb.org/software/lemmy
While the other replies are not incorrect, what they describe is users on Reddit posting on different subreddits.
What I am talking about are lots of niche subreddits (many even about the same topic!) thus that out of the few people that are here, there is simply no content, let alone discussions of the present content.