IMO Canada and the US just has more depth on its rosters than the other teams at this age group. Lets not forget the Olympic results
(Gold, Silver, Bronze)
2010
Canada, USA, Finland
2006
Sweden, Finland, Czechs
2002
Canada, USA, Russia
1998
Czech, Russia, Finland
Hardly a domination by North American teams.
And how about the IIHF Men's World Championship
2010
Czech, Russia, Sweden
2009
Russia, Canada, Sweden
2008
Russia, Canada, Finland
Again no clear domination of North American teams.
IMO the WJC is not a clear indicator of hockey slipping away in the European markets, just that Canada and the US have the best U20 players on the planet to fill out 4 solid lines.
Now goaltending, well thats another story. IMO European countries are starting to develope better goaltenders than Canada and the US. But thats for another thread.