I got in on reddit super early. Every few weeks I get a message from someone referencing a comment a decade old, now either featured in some youtube video or coming up in their google search. It's unnerving shit and I check my politics there a lot more than I do here. Just as a matter of user safety it's good that our posts disappear after a month or whatever. Maybe it's eventually a few months or a year, but if we ever return to the normal model of forums preserving everything forever it's a big infosec risk.
It is right now because its growth vs user churn is flat, it's sustaining itself but nothing more.
The thing is though, a bunch of people are here because they think it can be more than that. The balance preventing it from falling into decline would be shifted if people started giving up on it being anything more. And once you go into that decline while also creating a user-culture against measures that produce growth then the future death of the community is essentially guaranteed. If they see it as a treat and want to keep it that way they also need to support a culture of aiming to grow the site or user churn will fuck over their treat eventually.
I suspect those same people will also say any online work performed on twitter or reddit or any social media is just pretend and not real and not beneficial though. I disagree with that position. I have seen far too many people become communists specifically because of the work of very online communists on social media to buy into the idea that only offline matters. Half this site were probably radicalised online to begin with.