A niche sub equivalent succeeding on, say, Lemmy would either require the existing reddit sub to close and migrate there or for the Lemmy active user count to grow to the point where a critical mass of users interested in that niche want to discuss it there. There needs to be some way on Lemmy to promote those forums as well. A couple of niche forums I'm subscribed to are gaining a little traction, but I only found out they existed when they were mentioned on the reddit subs they're based on.
