Self-publishing is now a fast-food book industry. If you want to financially succeed, you have to be able to produce an enormous quantity of books in a short period of time. You also have to publish in the most popular genres and those are but a few (romance, erotica, thriller and crime, fantasy). To succeed in these, you need to follow the prescribed plot-frame and add mandatory ingredients these readers expect.
There is not enough interest for less poplar genres and books that challenge the readers, make them look at things from a different perspective, and contribute to the treasury of human knowledge and thought.