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.