[buckler]

To add to this, it also feels as that in most cases, for every topic that a niche subreddit (or multiple similar subreddits) covers, there usually exist better online communities dealing with the same topic elsewhere on the Web.

For example, let's say you're interested in airplanes and aviation. Relevant subreddits such as r/aviation just doesn't compare to communities like airliners.net with its sheer amount and high quality of content.

Quality of content aside, other communities in such instances also seem to have better organization, more strict moderation (although some subreddits do have very good, dedicated moderators), and certain culture that's not prevalent on Reddit (e.g. compared to some other communities that I visit, there doesn't seem to be a culture of searching before posting on Reddit, ultimately resulting in a lot of reposts), leading me to go to those places rather than the subreddits that cover the same topic.