I’m not sure what you mean by “catch on”
MLS is averaging almost 20k fans per game (19 teams)
World Cup tv ratings are in line with the NHL playoffs and are up about 25% over the 2010.
(I’m not a soccer fan, just pointing out facts)
Maybe so but that hardly makes it mainstream. You can also pack 20K fans dressed like Darth Vader into a Star Wars Convention but that doesn't make it a national pastime.
I was watching one of the games at the hotel bar the other night and noticed that the time counted up instead of down like it does in other sports. That's just weird. I'm sure the game holds a certain appeal to a small subset of Americans, kind of how certain people like Jimmy Buffet music and listen to it all day long in Hawaiian shirts while sipping from margarita glasses. Nothing wrong with that, especially if you happen to be in Hawaii or out in the Caribbean.
If I lived in Portugal or Brazil, I might like soccer more.