The main reason I see people leave a community that is based around a specific conlang seems to always be because of other people.
Which, for auxlangs like Esperanto and Ido, is a little bit ironic? Maybe? Since they’re designed to bring people together. But politics (how words should be used, when words should be added, etc.) and the debate (or, more regularly, arguments) for/against really seem to drive people away.
With Esperanto, I see this most with trying to expand vocabulary to add more inclusive terms, people being against that, and the resulting vitriol driving away people – mostly women and LGBTQIA+ people. I have a contact in the Ido world who has made a lot of Ido content who now tells me that they’re leaving because of conflict over words in Ido as well, and someone being toxic about that.
I’ve put a lot of energy into Láadan in hopes of building another type of community, oriented a bit more towards me and mine, but as things grow, it seems that there will inevitably be people leaving no matter what language or what goals are shared by the users of the language.
It’s almost like humans are the reason behind conflict, not what languages they speak. ;P