I grew up with the game accross the pond. As a teenager, the dream was to play in the World Cup, just like in Canada the dream is to play for the Stanley Cup. My first soccer memories were of Pele hoisting the crown in Mexico in 1970.
The best athletes in most soccer mad nations play soccer (actually it's called football everywhere except in NA). There is a large number of grass roots development programs, with many tiers and levels starting at age 8. Identification of top talent from age 10-12 onwards is customary in the better developed European nations. These youngsters are then developed by the junior systems run by the professional clubs, similar to what the Junior Canadians did back in the day prior to the NHL draft. In the big soccer countries like England, France, Germany, Italy, Spain and the Netherlands they have 3 to 4 levels of Professional soccer, with a top tier amateur level right below it.
The development system is vastly different in South America and Africa. They find their footballers on the dusty pitches, just like MLB finds baseball players in the sandlots of the caribean, and the Colleges finds basketball players on the courts in the hoods. In more recent years a lot of young prodigees from Argentina and Brazil find their way at an early age into the youth systems in Europa (Romario and Messi are two good examples).
While they have come a long way in the last 25 years, both Canada and the US still have a long way to go to match the European system. The US can compete somewhat due to sheer numbers. Canada is not so lucky, plus it is hard to play soccer there in the winter.
For comparison, there is no professional system in the Womens game, and so the US is actually a dominant nation in soccer on the female side.