Retellings and Nostalgia in Literature

There has been a surge in new and upcoming book releases being retellings of old stories, whether they be classics (for example, Frankenstein by Mary Shelley) or fairy tales (like Beauty and the Beast). What does this suggest about society at the moment, if literature is a reflection of our current state of mind? Are these retellings to do with nostalgia or a need to bring the past to the modern age? Do authors succeed in doing so?