Well, now that this thread has turned to talk about soccer:
Ironic as it may seem, the fact that we are indeed the "biggest developed country" in the world may be impeding the skill and quality of play amongst our soccer players, even despite all the other major sports that dominate our market and public interests. The fact that young boys and girls in America have to pay exorbitant amounts of money to play and receive formal coaching in this country places soccer as a sport that is more easily accessible for wealthier families. On top of that, the future of a promising soccer player in this country is rather limited, unless he has the potential to be recognized by some of the European clubs (Pulisic). Most promising high school studs end up as another D1 player who may/may not play in the MLS, a league that is far inferior to the talent of other worldwide leagues. Yes, part of this is popularity. But, also look at our training programs.
The dogma of formal training in this country for this sport that relatively favors utmost mastery of technique and foot coordination over sheer athleticism alone emphasizes progressing from softer, smaller soccer balls and smaller fields/goals to "age-appropriate" incremental increases. Meanwhile, around the globe, kids are running around on full sized pitches kicking adult-sized soccer balls since they were 8 or 9. It is no wonder why 15, 16 year olds in some of those countries are running toe-to-toe and are displaying ball IQs similar to their 10-20 year older pro teammates. This kind of mindset to this sport also limits the potential of our players, as well as the popularity. Compare this to our traditionally popular sports like basketball or football. The rim height and basketball size that club 10-year olds play with are identical to the dimensions of the NBA (despite the slight court size/3 point differences). In both of these sports, the biggest progression from the youth to pro level is mainly the size/strength/athleticism of the athletes themselves.
Tennis is a good example of how systemic changes in training methodologies can ruin a sport despite the relatively popularity of it (in fact, tennis is the fastest growing sport in the US in terms of participation/popularity in the 21st century). Just about 20 years ago, the US was rampant with generational tennis talent. You had Sampras/McEnroe/Agassi/Chang/Lendl/Navratilova/Seles/etc. Ever since the USTA sparked this BS idea of 10-and-under tennis (using smaller racquets and foam balls at a young age for kids to master the fundamentals in an "age-appropriate" way), you saw a decline in the number of American athletes reaching the top 50. Since the 2000s, you had Roddick reach #1 momentarily (trained before this) and Sock/Isner making some noise. Ofc, you had the Williams sisters but their training via their father was also was completely unique and kind of mental from a young age. Like in soccer, the equipment and facilities needed for proper tennis training require $$$. But you did have a generation of greats that trained in conditions of the same accessibility. Whereas now, 10 year olds are running around on undersized courts with undersized rackets hitting Nerf tennis balls whereas 10-year old Nadals, Federers and even Agassis was beating grown men in their respective circuits.