There's 2 things to consider.

First since this is all relatively new there's a bit of a gold rush for starting communities, eventually a couple of major communities across instances will emerge for different topics and those will stick, this will make things a bit less impractical from the point of view of an average user.

Second is if we ever get functionality on lemmy to create the equivalent of a multireddit, where you can group as many communities as you want into a single curated view (either for yourself or shared to the instance) then this becomes a non-issue.

Once "multi-reddits" have been defined and implemented in kbin that shouldn't be an issue. I don't know what'll happen with lemmy, but it would probably be in its interest to implement it too.

Fragmentation is certainly a problem if you’re looking for Reddit-style cohesive communities, how much of a problem it is remains to be seen in my opinion. The risk with trying to do things the Reddit way is that one or two large instances become dominant and you’ve just got Reddit all over again.

One potential solution that I’ve been turning over in my mind is the concept of “meta communities” - collections of smaller related communities across the fediverse that can be subscribed to and interacted with as if they were one. Users could potentially vote on a smaller community being admitted into the meta community, or there could be some other requirement. It could even be done locally by the user through a browser extension. It’s not perfect but it’s maybe something to explore.

Alternatively we just get used to more compact communities again. Let’s be honest - do we really have to know everything, all of the time?

This is a problem that is big now, but I think can also be solved with maturing the technology in the future.

Right now I have multiple accounts for multiple bubbles, but I can easily imagine some app or website that can congregate the content coming from multiple instances and choosing the appropriate account for it to post/view with.

Thus allowing one to access bubbles that have shut each other off in one central place. Unless they do it by completely blocking sign ups in which case they isolate themselves willingly and that is also good in a way to have as an option.

If I can imagine all this as a random system engineer, surely some developers with a passion for this and open source collaboration etc. can too.

To me this fragmentation is one of the strongest suits. Instead of putting everyone who is interesting in technology together, (which is an very large group of people), you can subdivide people. Take AI/LLMs for example. There's a group of people who is really interested by them and tries to use these technologies as much as possible. Theres also a group of people who is very critical of the harms and negative side effects of LLMs. Instead of mashing them together in a single community, both can now discuss the same news from their own standpoint.

And no, I'm not concerned about filter bubbles. I think the problem is the opposite, the idea that we have to force people in the same space who do not want to be together in the same space. Just like we dont do that in real life, people should gather around with the people they want to be with.

You're right on that part. Federations works great with mastodon and its communities made of individuals directly interacting with each other's accounts.

But when it comes to interacting though communities already spread through instances, not only it makes it hard for people to follow all these duplicates, but it threatens the very principle of federation in a certain way. Because most people will eventually subscribe to the biggest community for each subject (tech, nature, photo), which often turns out to be hosted on the biggest instances...and that is centralization once again.

A solution could be for users to gather all the communities they subscribed to around topics. Then your feed would be a mix of these topics' groups and singles /c. Twitter does that similarly with its List feature.