Exiles comes to mind as my first example; after having rebooted and cancelled the book so many times Marvel decided to simply make team out of the top 5 X-men.
Other spin offs that fair a bit better when they're written as one-shots like Spider Girl (the new one not Spider-Man's daughter).
And then we get stuff like Gambit, X23, and the X-Factor, which become steady and eventually become ongoing. Why don't readers like taking chances? I know all the stuff I mentioned was Marvel but all the publishers do this