If you're running a Fediverse server, you don't have to keep growing forever!
Some of the most thoughtfully-run and well-moderated servers on the Fediverse close themselves to new members when they reach a sustainable size.
The Fediverse is also much safer in the long run if its members are spread out on many servers.
The Fediverse isn't a startup and there are no investors to worry about. The aim isn't to cash out or gain clout, but to build something humane and sustainable.