Charles Stross demolishes the common misconception that “the only two people that matter are the author and the reader (one puts creativity in, the other money: the rest add cost)”:
In summary, while it’s true that the author is the one with the creative input, they only do about half the work. And the other half of the job is not optional. The reason publishers exist is to provide for division of labour; if I did the other 50% to bring my rough manuscripts up to published-book-quality, I’d only be able to write half as many novels.