If niche stuff is most interesting to you, then you interests are niche, by definition. The stuff that is interesting to many people naturally tends to become mainstream.
Actually, I think a lot of niche stuff is objectively good, but never gets mainstream attention because it doesn't have a large enough marketing budget. (or never goes "viral")
You do you realize that everything that is mainstream was once a niche that eventually got the attention of millions of people? Computers, for instance.
