I just took a moment to search all of my recent blog posts, and was surprised to find that I haven't been writing much about the reasons to self publish lately. Maybe it's because I spend so many keystrokes writing about how to self publish, or the drawbacks of self publishing. The funny thing is, in person, I usually recommend self publishing to working trade authors. But when writers contact me through my website with their questions, it's frequently apparent that self publishing is unlikely to be the solution to their particular puzzle. It's rarely a road to fame and riches, and the energy spent trying to achieve fame and riches through self publishing might be more efficiently applied elsewhere.
The best reason to self publish books is because you've studied the publishing industry and decided that self publishing is the path that will most likely bring you a steady income and satisfaction in your work. It's also the least common reason people cite when asked why they decided to self publish. In fact, the few authors I can remember telling me that they had studied the publishing industry and decided to self publish because they would make the more money for less hassle were basing their arguments on the advertisements of author services companies!
Not surprisingly, the authors in the best position to weigh the pros and cons of self publishing against signing a trade publisher contract are authors who have already worked for trade publishers. But most authors who write for trade publishers earn advances and develop an "I get paid upfront" attitude that makes self publishing look very unattractive to them. I can't make an argument in favor of bestselling authors self publishing their literary fiction or nonfiction because I don't think it makes much sense. Bestselling literary authors get the best book contracts and other perks that should discourage them from going to the expense of setting up their own publishing companies, unless they aim to publish other authors books as well. An unhappy bestselling author is probably better off changing publishers than changing careers.
The authors who would likely benefit the most from self publishing are those who are in the worst position to give it a try; the hand-to-mouth writers who rather than advancing in their careers are spinning a squirrel cage to keep up with the bills. The problems keeping those authors from breaking through with some titles that would have a reasonable shelf life and contribute to the author's income and peace of mind over the long term are sometimes their publishers problems. Assigning or accepting book projects that have limited market opportunities because the publisher is risk averse is a major issue. Trade publishers have a need for product, and they will stick with reliable (ie, deadline meeting) authors whose books don't embarrass them, but which rarely sell enough copies to earn the author more than the advance. It's a tough way to make a living, and because such authors aren't all that difficult to replace, a single misunderstanding or shift in publisher personnel may leave the author out in the street.
Laying aside all of the complications of going into business for yourself and all the downsides of working for "the man", the question comes down to how much the publisher is really doing to sell the author's books. If the publisher's marketing effort is limited to listing the books online and getting them a brief stint on some chain shelves, the author is giving up the majority of the title's revenue for some design and editorial services that could be outsourced to freelancers. If the publisher is employing the author for titles in strongly branded series that pay five figure advances, it may be that the author has benefited greatly from the association. But it's important for trade authors who aren't advancing in their careers to at least look at their options in self publishing. If they're afraid of trade publishers noticing and adding them to a blacklist, I've never heard of such a thing, but there's always the mighty pen name.