There’s a maxim to the effect of “Just because you can do something doesn’t mean you should.” This holds true in self-publishing as well. It’s true that Amazon has removed most of the barriers to getting your book published and available for sale. The trouble is, it’s removed barriers to publishing the same way karaoke removed barriers to being a club singer.
The risk of encountering sub-par literature is not a terrible thing for many readers, or they wouldn’t be venturing to buy cheap e-books in the first place. But it could be a career-ender for the writer. If your first book is a bomb you probably won’t get another chance from anyone who reads it, regardless of how many more books you write or how much you improve. The Internet can be very unforgiving.
Suw Charman-Anderson discusses this in more detail in her article on Forbes.com.
That’s the problem with e-publishing. When there’s no one to tell you no there’s…well, no one to tell you no.