I think one point that hasn’t been mentioned so far is that many of the American sports, particularly Football and Baseball, are just significantly more complex than many other sports like Soccer. For instance, Soccer has one method of scoring, football has several; this requires many more rules to define. Soccer advances the ball through a small and simple set of methods, football uses several very different methods; each method requires its own set of rules to govern. Soccer has continuous action, football has segmented action; this requires more rules to decide when it start, when it stops, etc.
In that regard, I don’t think it’s necessarily fair to compare the rules of football to soccer. Some people love soccer precisely because it’s elegant in its simplicity. Some people, like myself, love football because of its complexity.
As other people have mentioned, I think the inherent complexity continues to add more rules because it has a higher degree of special situations that need to be addressed, like the Infield Fly Rule in Baseball. You also have the simple fact, again as someone else mentioned up thread, that many of the American Sports have taken things like parity, and fan interest into account, where this hasn’t been so much the case with other sports. Obvious examples of this are when Baseball raised the pitcher’s mound to reduce a batter’s advantage, or when football moved back where the kickoff is kicked from, to reduce touchbacks and increase action.
So, are there too many rules? I don’t think so. Knowing all the rules isn’t necessarily important to being able to enjoy the game. I know plenty of people who can’t name all the positions in football, and don’t know what they all do. Hell, I even know people who don’t quite understand how downs work and how and why the ball is spotted where it is. The important thing is that the sport is enjoyable to watch and is enjoyable to play.
If anything, I think there often aren’t enough rules, because when people make statements about there being too many rules, it’s usually either because they’re just upset that a particular rule hurts their team in that instance or because the rule is bad. I like the fact that the NFL looks back at controversial calls and rules each year and reevaluates them.