The absurdity of this thread actually got me to register, as an American it's sort of hard not to laugh at the ridiculous generalizations some of you are making. You all act like we Americans are some separate breed of human, but let me tell you, our heads don't explode when a match ends in a 0-0 finish.
All in all, this is very easy. The sports isn't as big here because we haven't had a high level of play league here, which makes the most interesting variety of this sport still European. Many people in the US support and follow European teams, which makes sense in two ways. First, the most talent is in europe, and when you include champions league football you've got a very compelling and entertaining product. It would be silly not to follow it because it's European. Secondly, all of our best players play in Europe at this point, so if you got into this sport via the World Cup that was here or some variation of our National Team, you're going to follow the teams those players play on, which sadly led many Americans to examine Fulham but that's beside the point.
It is true that the sport is surging here, but mostly at the youth level. Every young kid in America plays football with their feet at some point in their youth it seems. It's a more forgiving sport than baseball for the uncoordinated and it's cheap and outdoors, so it's got a mass appeal to parents. Time will tell if that translates to something as far removed as our National team, and I'd guess that it won't because overall, our best athletes are playing other sports, and for more than the foreseeable future they will continue to make that choice because there will be a lot more money in basketball, baseball, or american football for these athletes than there will be in the MLS. It'll probably take 3 or 4 dozen american youth trailblazers getting hyped and bought at a young age, sort of like the Adu saga, but the players probably need to work out better than Adu before anyone would seriously consider it.
Finally, as an American, some criticisms of how all of you follow sport. It's been one hell of a ride following the lot of you on this forum this season. Maybe there's another forum that has more of an analytical bend, but it's very surprising to me as a follower of many American sports how little thought goes into the arguments presented here. Maybe it's the nature of the sport in that it carries few statistics, but on any forum for the Boston Red Sox, as an example, people are just as passionate as you folks are, but when arguing about the team you always bring detail and data to the table. As an example, as a City fan I agree with the consensus that right now the midfield is not performing and it's causing serious issues, which is an improvement on the leakage the defense had earlier this season, but I've yet to see anyone try to use any pass completion % data or any other data set to try to see where the team is actually failing. Or, in the absence of stats, there's a true dearth of people really talking about formations and tactics, pretty much every thread follows the same guideline, initial post, someone mentions hughes, someone mentions mancini, someone mentions mourinho, everyone makes fun of MUFC, someone claims to be ITK, everyone harps on that person. There's a slight variation of this where if you say something negative you're accosted for not loving City enough, and the thread moves into yet another discussion about whether love for team should overcome ability to criticize it. I don't necessarily expect this last part to be particularly well received, but if we're going to talk about a society's approach to sport, I'd say that as an American, it's surprising to me how much of the approach of this team's supporters, at least, seems to be more about the soap opera than the sport itself.