It is actually much harder than most people realize. Traditional publishers these days, even the mid-level ones, essentially want a book that is "out of the box" publishable, a bringer audience of 50,000 or more, and the author to do all the leg work when it comes to promoting and marketing. Often with all expense on the author.

Sure, there are people that are throwing stuff up onto Amazon that shouldn't be, but there are also some really good writers that simply got sick of jumping through all the hoops the publishing industry puts in front of them while absolute dog shit like 50 Shades of Gray gets a seven figure deal, a series, and a movie deal.