I don't know, seems to me that the more mature, the more you will have tried and true formulas. But there will always be innovators trying something new, too, and occasionally one will hit with the public and revolutionize the industry.
I'm thinking of movies, which are going on 100 years old. Look at the vast amount of formula-driven, play-it-safe drek we are offered from Hollywood. So many slick, soul-less movies designed to cash in on opening weekend and then disappear. But creators are still out there trying to follow their vision, and every once in a while someone manages the backing and marketing to take off and influences the success formula a bit. Of course, it's just a matter of time before they get swallowed up by the businesses that grew huge off of innovation but no longer innovate.
Recent breakout indie game titles give hope. And the industry seems to be trying to find a way for the bigger companies to foster those indie visions.