Preface: I'd like for the fediverse to win, active on both mastodon, and reading lemmy; however, economies of scale in the present Internet does not favor that outcome:
* What we want is high signal/noise ratio.
* In the magic old internet, the bar for signal was relatively low, because it competed with books, and TV.
* The competition over attention has raised the bar over what "good content" looks like.
* Content like that don't materialize out of thin air, but needs an audience to keep it alive, and to grow, and select, and feedback
* The re-fragmentation of internet communities risks loss of economies of scale for the content creators to create or maintain high-quality gems.
Let's take something specific, say furry artists. Their content loop for reddit was: post cute pics on r/furry, if it hits quality bar, gets upvoted, and seen by ~1000s of people; 0.1% of those will commission a new drawing, draw the thing, get paid, post it on reddit, close the loop.
In a re-fragmented Internet: 1, a lot less people will be able to find those "gem forums" focused around a topic, and they won't browse it daily; and 2, the artist needs to spam their stuff to all the communities to get the fraction of traffic they have on reddit.
The outcome from this re-fragmentation _in our present time_ will be the "hallowing of the middle", the "hobbyists scaling towards professional", and people who are just really into the thing, and make some money on the side. In a re-fragmented Internet, you are either a fully professional -with competent marketing team- or you're doing it for the ~20 people sharing the same forum.
I understand that many people are expressing explicit preferences for there to be only that 20 people they chat with, or only the hobbyist / geeks to participate and _I'm happy for them_. What I'm claiming above, is that this will kick the professional ladder out for upcoming people to build - show - get attention for their stuff. And that creates a less magical Internet.