A writer writes.
A publisher reads, edits, markets, sells rights, hires designers, ships the manuscript to a printer, pays for storage and distribution, sends the bill, collects the money and pays the writer.
A bookseller sells the book.
A reader reads.
This can and will all change. The writer can pass the publisher. The writer will do so, if and when the publisher does not adapt. How to adapt no one knows yet. But making the same amount of money for doing less, never really worked.
How long will this transition take? No one knows. Will it start in textbooks, academic books, cooking books, novels, comic books? Will it start with writers, who still are the only source of original content? Will readers stop buying the same amount of books, because they just bought an iPad?
Will we see a replay of the movements and developments we witnessed in the music industry? Or is publishing books a fundamentally different business?
Nobody knows for sure. What everybody can know however, is that bookpublishing is really just a value chain. Every link in the chain has to add value. Pressures in the value chain are top down, bottom up and from the outside. Authors will have more power to decide whether or not to publish directly or collectively (remember UA in the glory days of cinema), readers will have more options to read and the biggest pressure as always came from The Outside.
Who will make the first move?