I think part of it is that if someone comes here looking for a Reddit substitute, they will be disappointed, but if they come here looking for something extremely distinct from Reddit, they will also be disappointed. A lot of fediverse stuff is basically an inferior Reddit clone and that problem was compounded by the huge wave of Ledditors basically hijacking the culture of multiple instances to just exercise their Reddit habits, making the comparison even more obvious and poor.

Lemmy needs to eat populations that aren't too big in order to metabolize them properly. Anything beyond that is going to get ejected along with some of what it could have handled if it was just that, and this will remain how it works until Lemmy figures out how to push people much harder to engage differently with it than with Reddit.