Will Call of Duty be Next?

Recently Activision's decision to cancel Guitar Hero has caused me to wonder if this is a pattern that is waiting to happen with all of the company's games; to be more specific: Call of Duty. Activision feels the need to release these games every year, and while the series' quality hasn't dropped off yet I feel that it might get that way if Activision doesn't start to understand that milking a franchise isn't good for business in the long run. Eventually people are going to get sick of buying a slightly enhanced version of the same game every single year. The company has just realized this with Guitar Hero, and they are canceling it simply because it isn't selling anymore. Why don't they just learn their lesson with GH and give Call of Duty a breather for a year? Wouldn't the reception of a Call of Duty every two or three years be better than the reception of one every year? Not to mention that people have more of an opportunity to purchase "Black Ops" as opposed to say, buying "Black Ops" when it gets on sale in the late summer only to realize that they have to buy Modern Warfare 3 by the Fall. People would be more motivated to buy a new addition of the series every two or three years because by then they might view the current installment as dull or boring. By then they will want something new. What do you think about Activision's decision to keep pushing a new CoD every year even after their dismal experience with "Warriors of Rock?"