There's a good chance that much of the material found in today's books may surface in electronic devices about the size and shape of current paperbacks. You could still take them to the beach and read them while lying on your back. If you equate books with lengthy creations of the written word, then you should have no worries about the future. The written word will be around for a long time. In many ways, it has no substitute.
Text is the medium of choice for abstract ideas and concepts.
Other media have very few alternatives for developing elaborate theories or complex, interlinked ideas. Words allow more room for imagination than video images do. And the contemplative act of reading brings a singular pleasure not found in other media. People won't give it up.