I think this highlights a very good point. It's totally ok for everything to gravitate to a central instance as long as that instance is run in a way that everyone is happy with. The key is the the moment something changes and users aren't happy, the decentralised nature of Lemmy gives those users an exit strategy - a way to replace the bad instance and carry on.

If a single Lemmy instance becomes the new Reddit and then pulls a move that angers the community the way Reddit has recently, users wouldn't be reduced to protests and hoping that management listen, they could just spin up new instances, mirror the content, and carry on like nothing happened.

Yes this, and I could totally see the startrek instance growing into a hub for sci-fi related communities for example. More important than whether we are spread out is that the possibility and capability we have to spread out or migrate instances keeps instances in check by ensuring they don't have leverage or lock-in over the communities. Currently I think the main risk is communities living on 1 instance, but better instance migration tools would mostly mitigate that - imagine if you could migrate a community (which in underlying activitypub terms is very similar to a user account) to a different instance, the same way mastodon accounts can migrate between instances and keep followers.

That's the thing, I don't want one instance with too much control over others. That is a gateway to reintroducing corporate corruption into the Fediverse

Yeah a lot of Lemmy instances right now are mostly based on country or language, so.tnrte is some making use of the decentralisation. I'm hoping an art instance would pop up, then I might migrate.