So how do you do this without jeopardizing the future for the kid? I'm going to speculate a bit here, and make some assumptions.
I believe that in much of the world, soccer/football is a sport of the poor. So taking a 16 year old Brazilian with mediocre prospects outside of football, and committing him to soccer, is an easy choice. Even in Europe, I don't think the best players tend to come from wealthy families, although I have no explicit evidence of this.
In the USA, Soccer is a suburban sport played predominantly be people with money. If I'm such a parent (and I am), there is no way in hell all my kid's eggs go in the soccer basket. The University system we've established works to mitigate this risk, parents can see their kid go to college and his athletic training comes with a fail-safe for a non-athletic future. In the U.S., college soccer isn't good enough and happens too late, so this doesn't work. But I believe that you will need to find a way for parents to feel their kid is protected, even if they don't make it as a pro.
Geographic diversity also works against the USA. If we have big camps, with a good private high school as part of the package, that works....if the kid can go there. How often is that the case? How many families would move on the off chance that their teenager becomes a pro soccer player, especially since MLS players don't earn that much anyway. How many moms want their teen to go hundreds of miles away to boarding school? In Europe, you can put on in say, Paris, and cover 1/2 of the population of France. Same with Amsterdam. It becomes feasible. Here? How do you do that? Some kid from suburban St. Louis is going to go to Atlanta? How?
I think the approach the U.S. takes needs to be a bit different. Not sure how we solve these problems.