This is going to be a short and sweet little history of Reddit. Reddit was founded in 2005.
Take a look at what Reddit looked like in 2006: https://web.archive.org/web/20061206235353/http://reddit.com/
Note that it didn’t have subreddits back then because the user base was too small.
Look at Reddit in 2008 (December 31): https://web.archive.org/web/20081231080128/http://www.reddit.com/reddits/
Politics had just 72,314 subscribers. Technology had 85,678 subscribers, and the “Nicher” Food subreddit had only 4,438 subscribers.
Lemmy/Kbin follows the same path. Initially, generalist communities like Politics and Technology will have the most momentum and gain subscribers, just like Reddit did back then. As the user base grows, “niche” communities will be able to sustain themselves.
Let’s not think about the Reddit of today, let’s think about Reddit of old. Rome wasn’t built in a day.
I’m not saying Lemmy/Kbin are perfect but fragmentation is a red herring. Reddit has a HUGE degree of fragmentation, look at how many news subs there are or wrestling versus squaredcircle ect. It’s not really an issue either, take the wildly different approaches Games takes to Gaming; each community serves a related, but unique purpose.
The true battle here is userbase and thankfully those numbers are climbing at a sustainable rate. If we ever get into the hundreds of millions of users it won’t matter how many cooking subs there are, there would be enough unique and viable ones that everyone would have just the one they were looking for.
There was always a main one though, the others were splinters that happened after the main one succeeded. The problem here is they are all small, all the same name, and competing with each other to become the main one.