Contracts and actors don't matter. There's always a way to cancel if the powers that be decide to. I hope it will be made, but only time will tell. Yes they have official announcements out, but many were made before PC didn't do as well as hoped. Many were made before the economic crisis that is hanging over the heads of people in the USA. One needs money to make films regardless of the actors they have. If the money is taken away, they won't have the film. If the investors are too wary of making another film that won't make what they hope it will, they won't invest in it. It's that simple.
I'm glad you thought the movie was spectacular, but many people were going to see the story that they loved. Since it was way different from the book and since it changed the spirit of several of the characters it's not hard to figure out why several people didn't like it or struggled with it. I struggled with a lot of it myself. I would like to see VDT as long as they follow the book. If they're going to change it up all over the place in the manner they did PC, they needn't bother making it as far as I'm concerned. But that's me...and several others. We're entitled to that opinion and it's honest. I love the cast and crew of the films, but I want to see the Narnia I've treasured for the last 30 years. No more, no less.