I think that will grow up over time. May never get to the level of Reddit but hopefully even if it is just a few people talking and keeping things going will give time for others to discover. Baby steps.

I'm new here too and I learned recently that if you're looking at the number of subscribers to a given community it is generally showing only the number subbed on your instance, not all of the instances combined. Often the number of subs are much higher if you look at one of the aggregators (I don't know any off the top of my head).

The niche communities on Reddit built slowly too. Just keep posting content to these communities. Potential new users are MUCH more likely to stick around and participate if it seems somewhat active.

This whole thing relies on a tiny percentage of users that actively participate and try to enrich their communities be part of that percentage.