No surprise. After a surge of reactionary, or curiosity, based signups, some will inevitably loose interest. In particular, the ‘bottom 10%’ of users, who weren’t/wouldn’t contribute anything of substance anyway, or possibly were annoyed by some feature or another that was different than Reddit. I similarly don’t care that more people haven’t moved from Reddit to Lemmy, as the majority who haven’t would likely make the place worse. When everyone can interact with something with even the most meager barriers to entry removed, the quality always declines.