It's sad because he started so well, with a decent movie. It mostly got notoriety because of the twist ending. But I liked Unbreakable too. Signs was well-made, but full of glaring plot holes. He makes fine movies, as long as you turn off your brain during them.
Holy crap, The Last Airbender was the worst movie of 2010. I bet it prevented a lot of people from being exposed to an excellent show (more on that later). The Happening was a joke as big as Zooey Deschanel's eyes. And Screen Junkies couldn't even get through the Honest Trailer of After Earf.
Well, to understand it, let's look at a break down. (money numbers are in millions)
|The 6th Sense||Unbreakable||Signs||The Village||Lady in the Water||The Happening||The Last Airbender||Devil||After Earf|
It's important to note that Devil was a very "M. Night Shyamalan Presents..." movie. It appears he had the story concept at least, but beyond that, I'm not sure.
Yeah, it looks like his movies consistently make profit, and it's no surprise to see low-rated movies make big gross (anything by Michael Bay, Pirates of the Caribbean, Dan Brown movies). But that's why theaters make you pay before you see the movie. As long as he keeps earning bank, studios will keep financing him, I guess.
But bad karma catches up eventually. You used to be able to count on him for a good movie. Or at least an intriguing movie. Or at least one that made you think. Uwe Boll makes movies, they probably make profit due to their tiny budgets and German tax breaks. But he's hated in our community.
So M. Night, you got to ask yourself what kind of legacy do you want to leave. Because you need to take a sharp look at what you're doing and decide if it's resulting in what you want.