Is marvel dieing out?

Marvel has been on a role with movies.  Now the next movie to release is Thor 2 The dark night rises and will be released November 8th 2013. Yet reviews have said that the movies are getting old and dryed out after the third Iron man was released. People are getting tired of Robert Downey Jr. as Iron man and some people are wanting a new actor which might happen since in the last iron man movie it seemed that he quit his iron man job by getting rid of his chest piece and blowing up all of his suits, but you never know. Yet some people are saying they are getting better each time being more mature and better action scenes.