As you said in one of your other post we should have sorted out his contract long before if we were that bothered about the possibility of losing him.
From his point of view he's 29 and probably doesn't want to waste the rest of his career at a club going nowhere, he's not got too many years left at the top to win trophies. Juve were supposedly interested but maybe he didn't fancy living in Italy that has to be factored in.