The rising costs of paper increased their conservatism and unwillingness to take a chance on new voices. Small to midsize publishers sprouted up, taking over some of the functions the big boys used to fill, and then the electronics explosion made self-publishing a respectable and affordable option for a lot of frustrated writers. All publishing companies are placing increased emphasis on market analysis in book proposals. More and more, authors have to be willing to do anything and everything that will help to promote their books. Since authors have to get involved in marketing and promoting even with a publisher, many writers are opting to self publish.
Shelf life is much longer.
If your book is selling, bookstores and superstores will keep it on the shelf. And strangely enough, that's bringing new writers full circle. Books such as The Celestine Prophesy and The Christmas Box were originally self-published. The larger publishing companies are now asking their book reps to scout out locally successful books. Writers today are wandering around in a confusing publishing landscape.