Didn't read the post, but the problem is that in most top soccer countries, soccer is the number one sport, light-years ahead of everything else. In the US, several other sports are more popular, which drains the talent pool. Kids grow up immersed in soccer culture in places like Brazil, Argentina, Germany or Spain in a way that simply isn't as common in the US.
I get this argument, and it is probably partially right, but is soccer really competing for the same athletes as basketball and American football? Basketball players are mostly too tall for soccer (other than goalie), and a majority of football players are way bigger than great soccer players. Baseball and hockey might compete for the same athletes, but a huge percentage of baseball and hockey players also come from…
You need to look at what sports an eight-year-old is playing in the backyard, what sports his Dad is excited about on the TV.
An agile, fast, coordinated kid who's coachable and wants to train hard but is going to grow up to be 5' 8" is not going to make the NFL or the NBA, but if they've got the athleticism to play in the World Cup... well, in the US that kid will be the point guard on the local high school basketball team and also play safety and wide receiver on the football team.
In India, they'd be a cricket star.