There's certainly a problem that many communities are quite niche and a lot of posts end up going unseen in both engagement and rewards. OCD has a channel for finding such posts but it's still not enough, again we still have that reliance on whales there.
I see this more that Hive is still massively in its infancy, people have their preferences and the things we'd consider niche here just don't get the same attention as something finance/photography/travel related would. For example I am pretty much the only person on Hive posting about comics frequently. There are a few others that do it a bit less often, but it's like five of us in total spread across different communities. They get next to no engagement due to how niche it is here, and would make next to nothing both because of that and because Hive Book Club (where I post) is also an incredibly small community.
Part of my own goal with growing my HP is that I want to start being one of those people that does find and curate such people. I see a problem and want to do my part to fix it. Whether the subjects directly interest me or not.