Yes you are right, niche markets can work. There is one business in my city who sells old historic photographs. He advertises for any really old photos of areas, buildings and scenes, buys the photos from the people and then reprints them and sells them as prints with or without frames. He always has lots of people milling around looking through the prints and seems to sell quite a few, clever business idea because he is just reselling photos that were taken many many years ago.
Or you could start up a photography website, where all the wouldbe photographers can discuss anything they like about photography, get hints about how to take proper photos, and show off all their skills
Get little commissions here and there for links to other photography sites, who want people to look at their sites, how hard could that be????
Oh.....wait a minute......someone else has already done that..... bloody Ricktas