[toyg]

This is the same in urban Europe, eh. But over here, particularly in Northern countries, basketball playgrounds are mostly used for football. In the end, if you want to play football you just need a ball and goals, which are typically simulated with a few (school) backpacks or jumpers standing for posts. It's the most popular sport in Africa for a reason...

I think the main reasons football is still lagging in the US (despite the undeniable recent growth) continue to be the same: the main sports (basketball, baseball, and gridiron) are culturally rooted in the mainstream in a way that nothing else can match.