This is a theory that’s previously been stated in log/39-normie-hypothesis.gmi, but I think it’s worth expanding on as it’s become very relevant with the recent Reddit shit-show actualizing just how bad that website has gotten along with social media in general.
I think the model demonstrate how the ’enshittification’ process is an inevitability with any social media that is run on a venture capital model.
An online community can be like a village, where you have familiar faces, collective experiences, shared values and so forth.
As long as you stayed in small, well moderated subreddits you did find what the OP describes as a community, i for one tended to shy away from the big ones and specially the default biggest
The problem is that smaller subs could be Eternal Septembered almost overnight by getting onto /r/all and being swamped by people with no interest in following the established norms. The UK politics sub after Brexit for example was never the same again.