I think I know the reason to Hook"s existence
I am pritty sure I have found the true meaning to Hook's existence, as well as Peter's, and the crocodile's. Here goes: The story is about Peter Pan, he is the main character. The story within the story suggests otherwise making Wendy the main character. Yes I said Wendy. Incase you have not noticed Hook is always played (in the traditional plays) by the same person who plays Mr. Darling. (Also, as a side note it says in the book that Hook was not born on the Neverland) The same happened in the Disney movie, the new one (with Jeremy Sumpter) and in the original play. Peter is Wendy's youth. The crocodile is time. Hook must kill Peter (or Wendy's youth) before the clock within the crocodile runs down and Hook can no longer hear the crocodile's tick and have time to run away. Once this time runs down Wendy will stay a child forever and never grow up. Yes I know Peter defeats Hook. Let me explain that as well: Hook goes peacefully to the crocodile (in the book) and if you dont believe me look at it yourselves because he catches Peter's "Bad Form." He catches this in his very last moment and then goes content to the crocodile. To translate that back to Mr. Darling, Wendy, etc. He went down knowing that no matter his end, Wendy would grow up. Some would say Peter is the Victor of this story (and he is in his right) but I also have no doubts that Hook/Mr. Darling won as well in his own small, but satisfying, way. I take it upon myself to read this book one night at least once a month. I have never loved a book more. This is only one opinion but please take it to thought and tuck it away.