Those genetic requirements come into play at elite levels, but you need to start young, when those differences are less obvious.

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.

The difference in sports culture leads to almost no talent getting wasted.

I grew up in a European (Holland) country and as boys we'd play soccer all the time, during school on the schoolyard, after school, in the evening and the vast majority of boys in my class joined the local soccer team (me included). Even though we were a local team in a small village, scouts of slightly more important teams would sometimes come to our matches.

Basically, because soccer is so ingrained in our culture, virtually all boys play soccer at some point. That combined with all the clubs that play at different levels, and the scouting network, virtually no talent is missed.

Put differently, when a new Cruyff or Robben is born, there is a high probability that he will be found.

Women's soccer is really a different story. It has only started to take off in recent years and at least as many girls seem to play hockey.

Of course, it should be said that the only sport that really matters is Korfbal/Korfball :).

It definitely is at the youth level. I don’t think any football or basketball pros could be soccer stars, but absolutely there are kids who are star point guards on their youth basketball team but top out at 5’8”, or football players who never make it past high school but could have been great at soccer.

Perhaps the kids that could be soccer superstars stick with basketball until they figure out they aren't tall enough for the NBA, but are too old or just never developed enough interest in soccer to become a pro at that. But if they didn't have that NBA dream growing up, they may well have become a soccer superstar?

Kids who are good at sport excel at it all throughout school years, then once they hit college age the smaller ones dont make it further in American football any more - but they still spent their childhood playing it. In e.g. Uraguay its probably opposite, the naturally heavy guys cant compete at top level soccer (Im guessing) and fall out of professional sports

I think it is less about competing for athletes and more about competing for national attention (in the form of sports viewership that turns into money and school programs).

For national teams you only need to consider outlier athletes not averages. And many of the most top athletes at sport A would do very well at sport B. If a country funnels 100% of kids into a single sport, every single genetically gifted athlete will be put through the same selection process. Imagine every single physically gifted kid going to tryouts of the same sport. That's Portugal.

I mean you could say that baseball academies in Brazil aren’t good yet either, but I wouldn’t say that it’s because they “don’t know how to.”

It’s just that Brazil currently doesn’t care about baseball that much and baseball first has to become popular, except they already have soccer plus even basketball is growing quicker.

In America, soccer just isn’t that popular and there are so many other sports that people currently care about more.