Self-publishing has been seen by the puritanical library book loving and story-telling community as a fad that they hope it goes away. Traditional publishing is what publishing is all about where your work is vetted by experts first and manuscripts are prepared that reach the publishing stage only after great scrutiny of agents and editors. One also gets the author advance money for the book. All the top literary awards honour books and give awards to only the traditionally published books.
Self-publishing works in much the same way but only in reverse. It caters to the vanity and ego needs of the writer who in turn pays the set publisher to publish his book and partly promote and distribute it. Here, all rights of reproducing the content are with the writer. He or she has full control of the content funnel. But first, the writer has to make the investment. Selling of the book depends on marketing, contacts, how the book is launched and then pushed to the retail channel. Many other services are there as you go down the self-publishing rabbit hole. You can get your book reviewed by a panel of experts and get a lot of other PR done along with co-branded marketing exercises all at a price. The subsequent books are sold at a discounted rate. The more you sell, the cheaper the price of the book becomes to you.
Ah, what vanity!