Really? That's the "only reason"? And while opinions are subective, its also pretty easy to measure them:
http://blogs.marketwatch.com/themar...icans-still-dont-care-about-soccer-poll-says/
Your argument is like saying Japanese RPGs aren't as popular in America as FPS games because Japanese companies bungled the development of their games. No, the answer is that the culture is simply different. Baseball is relatively more popular in Japan than it is here in America. Basketball is extremely popular in China but not in Japan. Rugby and Cricket are popular in Austrailia and few other places but not most of the world. Different sports for different folks.
While the growing number of hispanics in America are making soccer more popular, I feel its real lack of popularity has to do with the fact it doesn't provide the same level of drama as football. Even basketball, a sport that grew up around the same time as football isn't as popular because it simply doesn't have as many "do or die" moments as football. These do or die moments is what feeds football's entertainment value. Though not as popular, Basketball is a running sport that allows for many changes in advantage depending on who's got momentum at any given time. Momentum changes are easily tracked over time via the fact teams are constantly scoring baskets. The fact you get an intersparsed 3 pointer or dunk helps with this level of excitement.
Soccer doesn't really have this. Like basketball, its a running game, but it doesn't have enough scoring to allow for changes in momentum that are easily observed. Soccer's momentum changes are subtle. Then there's the constant climax denial soccer provides everytime somebody gets close to the goal or kicks a corner- that shit gets old after awhile.
I want soccer to succeed in the US. And on some level it is becoming more popular. I was in ATL's airport when the final moments of the World Cup were going on, and people were just standing an watching outside of every availaible restaurant. My sister (whom I was there to pick up) said people were watching it on the airplane as it was flying. Americans (particularly more affluent ones, as the article states) are certainly vaugely interested in soccer. But for the people in that airport, that was probaly one of the very few if only soccer game they will watch all year. We should be under no allusions that large numbers of Americans are going to suddenly start watching soccer in lieu of football and basketball. I think at best, soccer can get about where baseball is if FIFA and MLS executed everything perfectly. That's better than hockey.