Canada's population is much more spread out. Also, don't read too much into a one-off game, that's what makes these tournaments so unpredictable. In comparison, Canada's most densely populated area which is the GTA/Golden Horseshoe could field a best on best team that could take on any country in the nation, and a lot of that talent is still fairly young like McDavid and Marner. Also, how Europe supports athletes through club programs makes it much more accessible. If the League let the Leafs through money at the best 8 to 12 year olds while getting their rights when they turn 18, the game would be much more affordable, but that is not something that is accepted in NA Professional sports, so the Leafs or the rich teams in these market, have little interest in subsidizing kids through junior hockey.