I love soccer. I've loved it for decades, as a player when younger and much more svelte, as a referee and as a spectator. I had seasons' tickets to the NY Cosmos while they were in existence. I think soccer is a beautiful sport, and loved coaching my son in it.
All that said, I am at a total loss as to why soccer has not taken off as a major sport in the US. We have more kids of both genders playing it than any other sport. But Spider is right; the kids seem to gravitate away from it towards other sports. My son always liked baseball and football, and was a wrestler in high school. He even won an Honorable Mention from the NFL Hall of Fame for High School football players (he was a linebacker and fullback). He played in the AYSO World Games for the world kid's soccer championship twice. But he dropped soccer and started lacrosse, and that is now his main sport. Yes, he plays at a Division 1 college, and it pays for his tuition (thank G-d). But he just got tired of soccer.
I'm not sure what can be done to increase the level of attendance at soccer matches. I suspect, however, that the demographic trends in this country will make it a moot point, as Hispanics will be a plurality in the not so distant future. And that will take care of the soccer attendance problem.