Was asked the other day what it meant to be an indie author. Mostly what it means is that you have little structured support for the process of writing books and also the marketing of those books. You are on your own. Okay not completely. I have help with editing, cover design, formatting and some distribution aspects from two great people Saul Bottcher and Nas Hedron. Maybe it just seems like you are alone on most days.
It was great writing the Muckraker series with Stanley Nelson in that there was someone else involved who could provide a different perspective. His input was an important element in the authenticity of the story line regarding journalism. Although when in doubt, I just make things up--it is fiction.
The real challenge for an indie author is promotion/marketing. I would guess that this is not the strength of most indie authors. You write your book, deal with all of the details of having a finished book, get it on-line and nothing-- now what? Especially if it is your first book, unless you have done a great deal of prepublication marketing (costing lots of money, which most indie authors do not have), nothing happens. No sales, no reviews --nothing. I have no idea how many one-book authors there are on Amazon but I would guess a lot. It is very discouraging to have written a good book and no one reads it, because it is lost in the forest of on-line books for sale. So many of those authors I'm sure just give up.
I've been fortunate to have found a loyal following for my books. Winning some awards and having good reviews have helped me generate a base of readers. Reviews are a big part of finding new readers. I really appreciate everyone who has reviewed my books--of course, there are exceptions. Occasionally I will get a less than stellar review. Ouch! But mostly they are good. Reviews are a real key to selling books. And it is selling books that allows writers to write.