I have actually done that with a community I'd personally be willing to moderate already. Naturally though, filling a community with a subreddit's worth of content solo is a challenging endeavour.

Even some of the less niche communities, for example, Zelda, aren't really existant here yet either. I'd create them all myself, but I wouldn't be willing to moderate them all.

What we have here already is good, but it will take a long time to develop until it attracts the userbase necessary for niche communities to thrive. This is far from a complaint, in case it happens to come across that way, it's simply a fact.