I think the two biggest factors leading to the decline of free culture as a movement were: (1) Lessig (who coined the term "free culture" and helped found many

I think the two biggest factors leading to the decline of free culture as a movement were: (1) Lessig (who coined the term "free culture" and helped found many related organizations) leaving the movement to focus on e.g. money in politics, and (2) The absence of any big tent organization promoting free culture as a movement, rather than focusing narrowly on a specific topic e.g. licenses as Creative Commons does. I co-founded the now defunct Students for Free Culture, and we were trying to do this, but we were focused on the youth demographic. Nobody ever took up the banner for the world at large, and when SFC died it felt like that was kind of the end of evangelizing for free culture.