More information than anyone could possibly assimilate suddenly became available to everyone. This meant that anti-contemplation skills such as skimming, speed reading, and so on became essential. Books caused illiteracy. Prior to the printing press, it was not important for most people to be able to read or write. After the printing press, these skills were essential for success.
Every new technology changes what it means to be human and to be educated.
These changes inevitably disadvantage certain kinds of people who previously were advantaged and advantage other kinds of people who were previously disadvantaged. Today no one advocates outlawing the printing press, and no one will get rich by writing a best-selling papyrus scroll entitled Paper Snake Oil . On balance, it is almost universally agreed that books are good. The reason that the printing press changed society and education so dramatically has nothing to do with the people who were advantaged or disadvantaged. Books made more information available to more people more quickly and cheaply than anything which had existed previously.