To add, a lot of sites that “Fade into obscurity” still have active communities, they’re just not mainstream anymore.

I would prefer if it grew because so many communities are dead. It seems that only political and shitposting instances have constant activity.

For me it’s still not a real Reddit alternative. Which sucks because I’m permabanned from Reddit.

Correct. We don't have need to be growing. 40k mau are nothing to scoff at and is bigger than most other online forums who can feel very busy even with 1000. So long as we're getting as many users as we're losing, we're good. And the continuous enshittification of reddit will ensure there's always people looking for a new home.

Cancer grows continuously. Obviously we should model everything on that.

This is exactly on the nose. It reminds of articles I've read about the oldest continuously operating businesses in the world. Here's an example: https://www.theceomagazine.com/business/management-leadership/japan-oldest-businesses/

Note that one thing in common between many of these businesses, some of which have been around for nearly 1,500 years(!), is that they are family owned and operated. In other words, they prioritized stability over rapid growth. I feel that there's a huge lesson in this.

for a service/site/mom-and-pop shop to be sustainable without unending growth.

I've been on somewhat niche sites which have lasted decades, with waves of people coming in whenever related sites screw up and trickles of people leaving when an alternative community becomes more popular. It's a comfy, slow existence, which works for some communities, but not for ones like this which thrive on diversity and chattiness, rather than really well thought-out replies days apart from each other. On reddit-like sites, time penalizes how high a post goes (unlike a forum where years-long threads are very normal to see on a front page) so there is an inherent benefit in having consistent activity. That doesn't imply boundless growth, but at least sustaining a decent level of activity. We're not chasing ad revenue, growth for growth's sake is not what we want or need.

But with that said, a community with no new visitors can only lose them. That can be a slow process, but it's inevitable. Been there, done that. Again, doesn't imply that pointless growth is a good thing.

That's some serious copium, and the other replies are worse. "If you're not growing you're dying" is bullshit when you control a large portion of the potential market, but not when you're a bit player. Being less popular than a manifestly shitty platform like Reddit is not a flex and not a sign of long-term health.