This evolution is an interesting thing in itself. Each generation seems to develop its own take on them, reinventing what is currently relevant to it and morphing it into something new. In recent years there has been a resurgence of interest in folk tales and what they have to tell us and I think this whole notion is something I'm playing with more and more in my artwork.
Incidentally, one of the best books I have read on the cultural significance of fairy tales is Clarissa Pinkola Estes' Women Who Run With The Wolves. If you're at all interested in this subject I highly recommend it.