If you recall reddits growth many of their communities evolved as offshoots of a single generic community. This made it easier for people to see discussions they normally would not get involved in, and once the posts in a similar category reached critical mass it moved to a sub Reddit.
I think people are recreating their niche communities here but they are floundering since the user base is still pretty small. Maybe it’s best to post to the “big” communities until the time is right to move to smaller, targeted communities?
I will join plenty of niche groups, not because I have a specific interest in it myself but I enjoy seeing what others who do enjoy it have to say.
I myself have nothing to contribute but like seeing other peoples interest, not sure if that makes sense!
I would go bankrupt perusing half of my interests but I love to watch other people spend money.