[j_w]

I don't know why any reply disagrees with this.

Look at basketball in the US. The best players will tell you all they did as a kid was play basketball. You can go to anywhere somewhat populated and the outdoor courts are in use almost all the time school is not in session for pickup play. Outside of structured practice (if they are on a team), many kids are still playing pickup games or shooting casually.

Soccer fields rarely get use outside of structured play. Kids that play soccer in the US just don't play as much, so their skills are (on average) much worse.