It is probably due to a number of people stopping using their alts after some instance hopping.
Also a few people who came to see how it was, and weren’t attracted enough to become regular visitors.
Curious to see at which number we’ll stabilize.
Next peak will probably happen after either major features release (e.g. exhaustive mod tools allowing reluctant communities to move from Reddit) or the next Reddit fuck up (e.g. removing old.reddit)
Stats on each server: https://lemmy.fediverse.observer/list
Improved moderation tools would help, however are you familiar with the filtering/muting tools available on Mastodon/Firefish/Misskey? These, coupled with an ability by individual users to block entire instances, help relieve some of the need for more moderators to help by enabling individuals to essentially self-moderate/curate their experiences as desired.
I think both improved moderation and individual filtering/muting tools would help greatly both to encourage microblog folks to join in, and make the experience better for those already here.