The fediverse doesn't need perpetual growth. That's VC investor bullshit. You don't need to be posting on a platform where the whole world is present. Again more corporate bullshit. As is the "digital town square" thing. It sounds profound but it's pompous.
What made the internet so good was variety. Which is what reddit seemed to offer in a time when the older paradigms namely message boards were becoming antiquated.
What we got with the oligopoly of social platforms is watered down to memes and politics. It's right wing cultural imperialism quite frankly. People have been battered into fear of being who they are online because in this age of centralized internet has made it a war to remove anything unacceptable (aka "woke"). There's no variety. There's nobody being themselves.
The fedeverse will have arrived if it manages to achieve distinct varieties. On a technical basis it's perfectly positioned to achieve this. Right now it's largely just reddit clones offering little more than an extension of the cultural/political wars embroiling the handful of centralized social media platforms.