I'm skeptical about football's future because of the injury thing leading to fewer kids playing the kid in the long run, and therefore fewer kids watching the game at all.
The greed and money issues have to play a part on some people as well. The length of the game getting close to four hours (from 3 hours only 10-15 years ago), and lengthy delays during the game also have to play a part. I can, without question, tell you they've changed my interest in the game, and how I watch football in general. I watch NFL games on "tape delay" with the DVR almost every Sunday, starting about 30-40 minutes late. By the time the second half starts, I'm almost caught up without missing any game play.
Also, soccer will continue to gain ground as one of the spectator sports of choice. Whether it takes from football or baseball is a matter of differing opinions. The reasons why are simple: 1) I'm the first generation who played the game, who got excited about the World Cup in 1994 in the US. I think it would have grown even faster if the multitude of games on TV were available back then. 2) We're consistently becoming a more global society, and football, not American Football, is the global game. American football, while popular in North America, is not nearly as popular as soccer worldwide.
My opinion only, but I feel like 25 years from now soccer will have gained ground, while football and baseball will have lost ground. Basketball, because it's a globally played game as well, will continue to be popular, if not more popular. And I didn't even mention Lacrosse, Hockey, or any other sport. Yeah, I think football will decline a little, and some of it's just because of the expanded options compared to 20+ years ago.
Spot on! Heck, with video games and technology that's available now (and will be available in the years to come), do kids even play outside anymore?