Well Mythbusters nielsen ratings have been going down since 2009, but then nielsen ratings for ALL tv shows have been going down since 2009 because fewer people are watching TV shows on televisions anymore. I liked Mythbusters more when the hosts were acting like themselves, before they started acting like characters, nickelodeon style. Ten years is a good run for something that isn't story based, and yeah, after about 100 episodes you start feeling like if you've seen one episode of Mythbusters you've seen them all. According to the stories I've read Tory, Grant and Kari didn't leave voluntarily, they got the ax. It's about ratings, they're reverting to the old format hoping it will improve ratings, it's not about Tory, Grant and Kari being too expensive. They're trying to stave off cancellation as long as they can.