I agree that AT aims high, maybe a little too high.
To me Fediverse is basically all the forums we had in the 90s and 00s, but now they can talk to each other. So with that said, I am principally against huge instances like mastodon.social and such.
While bsky is more like decentralized Twitter, meaning it also requires a significant chunk of the resources of Twitter to run consistently. Which is also why it has not decentralized yet, and probably won't any time soon.
We have to ask ourselves, what is the point of decentralization? What is the USP?
To me the USP is that no one person or entity can buy it, sell it, or ruin it.
If we had to start over from scratch then I think AT would be a good way to start, because it would presumably not be federated with bsky and therefore low volume. But as volume grows it becomes harder and harder to maintain for small groups and eventually they all consolidate into big groups that are easier to take over and ruin.
Basically it's a difficult decision we have to make, a trade-off between consistency, and decentralization. Which do you value more?
Me never having been on Twitter, and coming from that era of the 90s and 00s, I value decentralization and small groups participating in a federated network more than large entities.
How I envision the future of social media, all these actors like bsky, Twitter, Meta, Fediverse will continue existing side by side, but Fediverse will likely be the smallest and most niche of them all. Fedi has, to me, taken the place of all those old message boards I used to hang on, while the rest are mainstream social media that made its entrance onto the world wide web back in early 00s with Facebook.