When this article in the Economist announced that IKEA was redesigning its Billy bookshelf to have deeper shelves in order to accommodate things other than books, many concluded that this signaled the end of the book.
From what I can tell, the depth of the shelves is the only change, meaning that the shelves will do a better job holding deeper and/or over-sized books. Unless IKEA reduces the weight capacity of the shelves, all they have done is make the Billy bookshelves that much more versatile.
Once could say that if IKEA is in fact adjusting its marketing of the Billy bookshelf away from book storage, that this points to a trend that book storage is no longer what its customers are looking for, meaning that the 'demise of the book' theory isn't all that off base.
You could also say that IKEA has taken note of the various uses people have found for the Billy bookcase and determined that with this small design change they could increase the versatility of the shelves that much more and in doing so increase sales. This is the explanation that rings truest for me.