Self-publishing is easy these days. You write your book and then you either pay others to get it print-ready, or do some or all of it yourself. But every manuscript must be edited, every cover must be designed, every book must be designed, text must be indexed, the eBook must be designed, rights must be secured, and an ISBN must be obtained. When ready, a printer must be paid and books must be warehoused and distributed (or printed on demand, at a much higher cost). Then the book has to be marketed, at book shows, at librarian’s conventions, to West Marine book buyers. In short, there is a lot of time, expertise, and money required to get a manuscript turned into a quality book and then put before potential book buyers. The primary advantage of self-publishing is that the author(s) makes more money for each book sold (assuming the publisher offers no advantage in terms of increasing sales, perhaps a bad assumption).