The other factor here at play is that most of the American talent pool has been a part of the US National Team Development program for teenagers, or played in the World Juniors, so they are well known to the USA Hockey brass.  Canada does not have a standing national team development program for 16, 17 and 18 year olds, as they have the far larger CHL/Major junior programs to do that level of development for them, so it's not surprising that their management needs the extra tourneys in Europe to evaluate talent that the USA might not need....