I’ll believe soccer is more popular than American football when I see non-Asian immigrants playing it in pick-up games. Because Asian immigrants are the only people I’ve seen playing it where I live. Every high school in the area has a soccer team, and their scores are all reported in the papers and on tv. But I wonder if anyone plays it outside of school.
I think once you get a couple of American players who have some success playing in the big European leagues, that will inspire more kids to get serious about playing the game, and more will eschew other sports to focus on soccer, especially if the health concerns about playing football cause more and more parents to not allow their kids to play it.