The era of niche subreddits is over these days. Reddit started ignoring subscriptions and just pooling all posts together and suggesting things the algorithm thinks you are interested in regardless of subscriptions.
I think it goes further than that. Since IPO a huge number of subreddits have been shut down and the disappearance of many moderators. I don't have any way of proving what happened, but it seems awfully coincidental and the result of some private policy change. Reddit has a huge thumb on the scale on their own platform and it is not healthy.
