let’s address the possibility that like mastodon/matrix 99% of ppl will flock to the biggest handful of servers

That’s just human nature. There might be things to do, but they’ll only have a small effect.

What is the real value of decentralization given that? Outside of like political unrest.

The ability to easily switch. A protocol to automatically migrate an account could he nice.

And what role do small servers really do in that landscape?

They keep the big servers honest.

let’s address the possibility that like mastodon/matrix 99% of ppl will flock to the biggest handful of servers

This doesn’t appear to be happening in a serious way. There are 7 servers on join-lemmy.org with more than 100 active users, which puts them within 10x of lemmy.ml. It’s not clear to me that this is a major problem.

But even if users to substantially centralize, these things make Lemmy categorically different from centralized social media:

• Even just two instances that interoperate and are run by different people/groups is MUCH more robust against bad admin behavior than 1 instance with no interoperability. If either set of admins starts doing something extremely unpopular, there’s very little barrier to folks migrating to the other instance. Doing so doesn’t even cut them off from communities on the other instance… Though if the problems are serious whole communities can move as easily as large groups of people can agree to do anything together.
• The ability to stand up new instances makes Lemmy MUCH more robust against the admins of the major instances colluding to something extremely unpopular. It’s not EASY to stand up a new instance to serve a large user count, but it’s possible, which is more than can be said of reddit/Facebook.

These two properties act as incentive to “keep admins honest”, and as a powerful escape hatch if they behave badly. They have a cost in that it’s easier for communities to splinter for stupid reasons, and for people to “take their toys and go home” over small disagreements. But they make the ecosystem as a whole much harder to hijack. If people aggregate on big instances, it’s because those instances are run well and people like being there. If those instances stop being run well, the ability for anyone to stand up alternative instances that interoperate enables people to leave badly run instances with a much lower opportunity cost than leaving a centralized social media service like reddit, Twitter, or Facebook.

I think it’s almost inevitable that users in their initial migration will troop to the more visible aka biggest instances. In time it should level off and people join a handful of the bigger federating instances

I joined Lemmy very recently and the concept of the different federated servers was easily my biggest stumbling block in signing up.

At a glance, it’s really hard to tell what choosing a server represents. Even now, I’m pretty fuzzy on it and could barely explain it to my partner.

Even after getting a rough idea of how the federated server concept works, it’s not easy to know which server has the right vibe/ content for you.

This, to me, is the biggest cause of congregating on the larger servers. Without a resource that can easily explain the differences between each server (and why it matters), it requires more effort than the average person is willing to expend to choose a non-“default” server.