Soccer is different. It certainly isn't for everyone or even for all sports fans in general.
Oftentimes, the most exciting things in a soccer game are things that almost happened. Something like 25-30% of league games end in ties. What non-fans of the sport deride as "wasting time kicking the ball around" is not that, but does appear that way to people who don't know soccer strategy. What's funny is that I've heard Europeans make statement like "how is American football so popular; most of the time spent during a game is guys standing around or in a huddle." That's completely true, but I don't think that makes watching a game not exciting. It's a matter of your perspective and what sports you are accustomed to seeing.
I think what has actually caught on in the United States relative to soccer is not the sport itself but the US Men's National Team. MLS is not and I don't think ever will be a big deal because the money, tradition, and power structures of the sport are always going to be in Europe.