Self publishing has become such a hip concept that you sometimes wonder why we need those stuffy institutions. Well, wonder no more, because they fulfill a real service by allowing you to focus on creating and they take over the nightmare of selling.
Why is it a nightmare? As I slave over my Nanowrimo work, I am filled with doubt. Am I writing the right things, who am I writing it for, is my work actually something others want to read? 
In a way, splitting the work into blogpost actually achieves a valuable goal. It allows you to split up, measure, and adjust your work to market demand. At the same time, long form storytelling cannot always be produced that way. Sometimes, as you write a chapter, you figure out that the order’s not quite right, perhaps the transition doesn’t make sense and something needs to be rewritten, etc. So perhaps serialised work is not the perfect antidote to the creation vs consumer insight problem. 
On the other hand there are two ways that may be. One may simply be the market effect of consumers choosing the strongest content and not choosing the weaker one. I compare this to the Amazon or Apple App Store market places and rankings, where customers vote with their dollars and reviews. A simple mechanism that costs 30 cent to the dollar as a standard fee.
The second would just be outsourcing to a publisher, who not only selects a book based on estimated market worthiness and then attempts to place the product in front of customers’ eyes. It is not an exact science either, but it often feels like the most viable one when it comes to publishing books that require a lot of time, cost, and uncertainty (risk) to produce. 
Maybe, by my way of reasoning, you can see that I derive much of my thinking from different sectors (high tech, space tech, medical), and try to apply it here. In the end, I just want to understand the raison d’être of the publishing industry and where creators fit into it.