In Canada our #1 sport is hockey, it is rarely played as a school sport until college or university. Soccer is the fastest growing sport. It's played from on community teams from age 4 and on school teams from grade 6, I think...
Germany has one of the best football teams in the world and some of the best players? Where did they learn to play? Do they have a system of community based teams only? Do kids not play soccer/football in school at all? This seems odd to me.
I've traveled a fair bit and no matter where I've been, it seems to me schools always have a field, an clear area where kids play games. I've stumbled across quite a few pick-up matches. I've watched cricket in India and baseball in Puerto Rico. In Thailand, my hotel window overlooked a school yard that seemed to have an endless soccer game going on. These kids played because they loved the game, like most people who play sports. They wouldn't try out, go to practice or get up early for a game if they didn't love the game and want to improve.
I think sport in the US is a wee bit different though, in that, it has been something that has always seemed to cross the dividing lines. It's the only thing in the US that doesn't care what colour, religion, where you're from, what you do, how fat you are, if you're handicapped or gay... everyone can be on the bandwagon, everyone can join the club, there's an understanding among fans that if you're wearing that jersey or hat, you'r family... At least until the game is over.
Every time I've been south of the border and we are in a boring long line up, my husband and I have a running joke. He'll starts talking about sports and the whole line of people eventually jump in and start talking, it's amazing. I keep waiting for the day people will look at him like he's from Mars, hasn't happened yet. People don't feel threatened or uncomfortable talking about sports. It may seem like a pack mentality, but I think it's more than that, it's an identity of common ground.