Since Fortune 500 companies took over the conventional publishing world, there has been a 90-10 rule. The top 10% receive all the editorial or promotional support. The other 90% are just published and left on their own.
Upon the collapse of the economy in 2008, brick-and-mortar bookstores started to close. This opened up the opportunity for authors to start self-publishing. Stephen King, for one, with his huge popularity, tried this with a digital version. People still wanted the actual book, though, not a computer screen or a stack of printed paper.
Enter the digital reader: Nook, Kindle, iPad, etc.
This new way of publishing with technology fast-tracks what was an unprofitable and lengthy process into an opportunity that emulates publishing in its heyday.
When not relying on outside entities to publish, authors and their books have the ability to be profitable without being in a vulnerable and unsecure position.
Personal Note from Tom:
I highly recommend that you familiarize yourself with the ways and means of book publishing before delving too deeply into the process.
Do so easily by watching this video.
The Current State of Publishing by Tom Bird