I see lots of communities with hundreds of subscribers, but no posts. What is with that? If you’re going to register a community, at least help it get going. Post some content regularly, until it becomes self-sustaining. It’s disappointing to open a community with hundreds of subscribers and not a single post.
Those platforms die off because they have a profit motive. No content -> no profit -> no platform.
Admins can stop paying their hosting bills and drop from the network, but FOSS doesn’t have that problem. It exists for the sake of existence.