Because we have 4 other sports that originated in the Americas: basketball, gridiron football, hockey, and baseball.
If you like soccer, perhaps you'd like to try our faster, more kinetic version, called hockey. It's the same sport (goals and such), and you get to watch it in air-conditioned comfort.
Or if you still like the "players are fragile" model of soccer but want more goals, we also have basketball. It's the same sport, and you get to watch it in air-conditioned comfort.
Or we have two other sports that are totally different.
Football and hockey require a serious gear/facility commitment, but baseball and basketball don't, so there's something for everyone.
Basketball players are almost a completely separate population from soccer players. The shortest basketball player would almost be too tall for soccer.