Fediverse

Reddit's drawcard was finding THE sub for a topic

IMO Reddit's drawcard was containing the sub, and therefore the community, for a topic. Reddit is where the discussion was, and for many communities still is. Rather than hosting a dedicated forum, people interested in starting a community can just start it and begin moderating and discussing without setting up a backend; it allows users to get to the "socializing" step of building a community in less steps. Lemmy also does this, albeit with a smaller community likely distributed over several instances and earlier in the system's lifecycle.

Hopefully, Lemmy will implement a "multi-community" option like the multireddit concept so that users can group multiple related communities into one feed.

That being said, I think that similar communities ought to find each other and work together to best serve the people of their communities. Some communities will benefit from collaborative non-competition (for example, a community for discussion about how to use a specific complex product) while some have no need to be centralized (for example, a community for sharing dank memes). However, even in communities that would benefit from non-competition in good times, users should always be free to form their own communities in case the parent community (or their moderation) becomes too odious to bear. This process was much more difficult on Reddit because sub names had to be unique, so new communities would need to pick a weird name.