The real issue is the lack of understanding of the game. American Football is like a Chess match played with athletes. The complexities and intricacies are lost on those who don't have in depth knowledge of the sport. Unfortunately it take years to really understand the sport. In The United States kids grow up watching and playing football, therefore there is a broad base of knowledgeable fans. The NFL has yet to realize this fundamental problem. I don't believe simply having top tier players and teams in Europe are going yield significantly different results than NFL Europe. The reality is that it is going to take decades of exposure before it will catch on. Until they get kids playing the sport, the sport will not catch on. I really think they were better off with the NFL Europe model, but should have expanded it to provide support for youth football. The reason why other American sports have had more success in expanding around the world is that they are much easier to learn and understand.
Because we all like to watch Chess?

