E-books are becoming an increasingly popular trend in regards to reading and literature. Many books are making the movement to digital format, leaving physical books to eventually whither away. It makes sense, considering all the conveniences of E-books. The portability of an entire library, the reduced costs of each book, the ease of obtaining more books. As technology progressed, E-books even gained functions that were thought to still be unique to physical books. Highlighting text, writing notes, among others. This essentially leaves physical books with nostalgia as their strongest factor.
All of these changes however, should be expected. After all, the progression of books throughout history has been similar. Scrolls were replaced with the bound codex for increased portability and manageability. From papyrus to parchment to paper, for cheaper and more easily mass produced writing material. From writers to presses to printers for the same reason. Now E-books cut down on ink for text, cut down on the materials needed for books,cut down on size for portability.
This natural (or I suppose mechanical) progression from books to E-books is just the modern take on past repeated processes. That being said, this stage of progression will be finalized when E-books are the primary form of literature, with things like the codex as artifacts of the previous generation. With the difficulty of managing security for E-books, that generation is still a ways away, but still bound to happen.