The idea of watching a bunch of guys run around on a huge grass field where, every once in a while, someone eventually scores a goal is not exactly entertaining. This is really the only exciting part of the matches, and they are few and far between. It is common for matches to be really low scoring. We, as Americans, want to see a lot of points on the board, and will always tune in for even the remote possibility of seeing someone get taken out in a horrifically spectacular fashion.
Sure soccer has its fair share of injuries, but they are more likely to happen in sports such as American Football, Ultimate Fighting Championship, Hockey, and Basketball to name a few. Sure there is Rugby, but this is one sport that few Americans even understand, aside from Cricket (no one understands Cricket). It is a bit like football but without the pads.
Basically Americans require a sport where, even if they have never played it, they think they know more about it than both the players and the coaches combined. This is also why Baseball is popular as well. Sure Baseball is not as fast-paced as Football or Hockey, but it has enough going on, most of the time, to keep spectators interested in the outcome.
Football, has action pretty much on every play, and the potential for seeing someone get creamed, whether they are anywhere near the ball or not. Plus there is the possibility for some really high scores.
UFC, is pretty self-explanatory. It is even becoming more popular than boxing. This is where grown men, who have been studying every form of fighting from Karate to Brazilian Jiu-Jitsu, climb into a cage and beat the snot out of each other. Oh, and break a few bones as well.
In Hockey you wait with baited breath for a break in all the fighting to see a goal scored.
Basketball is non-stop action from the very tip-off, and the scores usually end up somewhere between 80 to over 100 points for each team. And there is the chance to watch your favorite player flop around on the floor like a freshly caught trout, which is always fun to see.
Really, the only way they could make Soccer more watchable is by making the field smaller. It would help speed up the action, since they would not have to run as far, and there would be a greater chance for someone to score. Even on accident. Regulation soccer fields at the level they play at the world cup is longer and wider than a standard football field. The dimensions are 130 yards long and 100 yards wide. They should reduce that by at least a third, if not a half. Then we will see some much higher scoring matches.
After all, it is just for entertainment, right?