The first airplanes were a niche, and so were the first cellphones. Facebook was this social network for ivies.

Just because a technology is currently in a niche position doesn't mean that in the long term it won't be a revolution or won't become mainstream.

As far as I've seen, Magic Leap doesn't even have a niche. I can think of plausible niches for some hypothetical future AR tech, but none for what Magic Leap has managed to create.