I think if you were to go a long way in the competition, the sport could erupt over there.
The truth is that soccer is already very popular in the US.
When I first lived here more than 30 years ago it was a different story. I used to play in a regular pick-up game every week and it was was 75% international -- Brits, Brazilians, Argentinians, Italians, etc. The Americans who came tended to play as if the idea was to run straight through your opponent. Tough defenders, but probably wouldn't have lasted long with proper refereeing ...
It's very different now. Not only is there a very solid base among kids, but a lot of people follow it regularly. There was a very interesting piece recently about how MLS is flourishing by having purpose-built stadiums in urban areas -- notably, not in Boston -- and that many of the fans are young Brooklyn-Portlandia types. In fact, one of the most knowledgeable and passionate soccer fans I have ever met was an American businessman in his 40s whom I sat next to on a plane a couple of years ago. He was on his way to Austria, where he'd never been before, but he told me he'd packed his boots anyway in case he could get a game ...
You won't hear much about all of this because as soon as people admit to liking soccer they will be attacked for being part of the "****ification of America" and so on. (This whole "true sports are manly contact sports" stuff is a bit of a joke for a nation that devotes a whole TV channel to golf.) I don't suppose they sell many replica jerseys.
Of course, nitwits like Bob Ryan will continue to write articles claiming that the U.S. isn't serious about soccer because ... er, how else to explain that the U.S. doesn't win the World Cup? But the fact is that soccer has a really solid and growing popularity and that's much better than a passing wave of enthusiasm.
