Those are all great questions, and, believe me, I've thought of them. I've been discussing niche ownership issues on their forum. There's one snag in the "ownership" department. It's not truly ownership. You lease for a year. So if I die mid-year, chances are, it would go to auction at renewal time. That is, unless I was wise enough to will it to someone and give them keys to my account, or give those keys to my testator. In that case, renewal would fall upon the person to whom I will it.

On a broader scale, there are plans for Narrative to allow niche sales from one owner to another. I don't have specifics, but I've seen it discussed.

Keep in mind, most people won't be interested in owning niches, or moderating them. They'll just want to create content. And there's nothing wrong with that. Right now, there are over 2,000 niches approved by the community that don't have owners. It will take a while, I think, before all them find their way to someone's heart. Maybe one of them could be yours. :-)