People will come up with cash for things they thing are worth paying for. A picture of a sunset has little commercial value, but custom photography (weddings, etc) do. The customer doesn't care about his overhead, especially if he doesn't know how to calculate it. Why should they? If you want them to pony up, selling something worth buying. Musicians have figured it out, why shouldn't he?
I license photos for publication. One of the best photos in terms of revenue is of a sunset. The cost of licensing is not very high, and varies on publication type & volume.
This photo alone has paid for the camera I took the photo with & the location costs several times over now. It may well surprise you, but there is a huge market for sunset pictures, as well as other even more mundane everyday items and scenes.
