I've been arguing for over 2 years now that the actual value proposition of the fediverse is Community+. There are several Lemmy and Mastodon instances that are built around this -- tenforward.social is a Star Trek themed and focused Mastodon site, where the vast majority of local chatter is focused on Star Trek, and startrek.website, beehaw.org, midwest.social, ttrpg.network, etc. are all community or interest focused Lemmy-based websites -- and they all seem to actually work in that model. People aren't signing up to the Star Trek Lemmy site to talk primarily about Call of Duty or American politics. They get their Star Trek community, and they can engage in those general interest discussions that are being hosted elsewhere, and everybody wins.
The key to growth, then, really is getting enough special interest and community websites up and running on the fediverse, and letting people discover the the power of being connected to people on other social media websites without having to sign up over there, too.
If Bluesky was using ActivityPub, there'd be no issue here right now. We'd all be able to get Community+Bluesky and be all the happier for it. But they've created their own system that's prohibitively expensive for the average person to utilize without having a direct connection to Bluesky's hardware, meaning the control forever remains in the hands of corporate interests and the rich. And that's just a play at being the next Amazon. We're either locked out, or we're under their thumb. And that's not really where any of us who are engaged with this fediverse project wanted to be.
I think this is because it's not a clear, cohesive place. Developers keep trying to make it look like centralized social media, but I don't think that's going to work in the end; it certainly isn't working now. Trying to dress it up as something that it's not, just because that thing is currently popular with the masses, does nothing but set us up for failure.
Mastodon is a second rate Twitter, Lemmy is a second rate Reddit, etc. The existing model of trying to make all of this look like one, single, central location is uncanny, and people notice that.
Lemmy's got some good theming options, and the templates are there to do custom theming work. There's the potential for some real website branding there, in that. But if you look at Mastodon, the biggest player in the game right now, the developers go out of their way to homogenize the Mastodon experience. Every Masto website looks fundamentally identical to all of the others. It's doing everything it can to make it look like "Mastodon" is a place on the Internet, in the same way that "WordPress" is not.
And that's a problem. ActivityPub doesn't really support that fiction.
Some ideas have been floated around in the microblog space, and tested in some places. Having 'Local' be the default timeline has worked out pretty well on Catodon. Strong community theming has kept tenforward.social on topic, with most people there discussing Star Trek. The art-based Masto instances work well, and seem to be fairly sticky. But generic, general "Mastodon" is failing to inspire folks, and lacks the pop culture discussion that the general public wants. Journalists have bounced, due to audience engagement tapering off. Communities of colour keep getting chased off of the big instances.
Attempts to occupy the "general" space and branch out into niche interests aren't working. The focus really needs to be shifted back in the other direction.