A single friendly game won't say much anyways.
Canada tied Brazil prior to 1994 Gold Cup. And it was the full Brazilian side which went on to win the cup two weeks later. But the tie did not mean that Geoff Aunger was world class. It was just one result on one given day.
Back in May, Argentina was probably playing around with their line up. For all we know, some of the players crossed out may have been as good as the ones that got to play, but were removed due to injury. Others may have just marginally got cut.
BTW, comparing Argnetina and Canada would not even be fair. Their U20 team dominated this tourney in a way I have never seen a team do. They controlled almost every game with the exception of the final and even then, when they decided to take over, they did it. I have never seen a team have such composure and such control at will. The Mexican game was the perfect example when they just scored a goal and against one of the best teams in the tournament, they just decided drop back and killed the game.
Very few teams will ever reach the level that Argentine U20 did in this cup, if any. If we can even raise our game to the same level as US or Mexico, that would be good enough.