I don't know. I'm sure there's a lot of stuff going on that we don't know about. The fact is, more films aren't produced than are, even after tons of money and time gets spent working with it. It could be that Pixar thought newt wasn't up to code. It could be a political or financial decision. The fact is, we don't know why.

But it does seem troublesome that most of the stories are now sequels. It's very hard to make good movie sequels. (Heck, it's hard enough making good movies.) Television, novels, and even graphic novels can handle long-running stories better than movies can. Part of this is that television and novels have more time to digress and explore. Movies don't have that luxury--something needs to be consistently happening in a very structured way in order for it to not feel laggy. Movie stories are larger than life. The problem is, there are usually only so many "larger than life" stories within a particular universe, and if you try to force it, it shows.