I don't know about the EU, but the US has much, much better support for scholastic athletics in almost every sport. You have a better chance of playing for a competitive high-school team with lower participation costs in the US than in Canada, where it is pretty much pay-as-you-play.
Plus the US has ten times the population, and hockey has become a popular niche sport for rich white kids in numbers that Canada can't match in the long term.
The tide has turned. Canada is competitive, but nothing more than just one of many competitive hockey nations.