Overall, the US played well. They weren't blown out by anyone and lost each of their four games by one goal. They lost to Sweden and Russia in the prelims, both of whom are now in the semis along with Finland and the Czechs. They played inspired defense but couldn't score.
It takes time for lines to gel, players have to anticipate where the others are going to be. That's why this was doomed to failure. The team should have been playing exhibitions for months before the Olympics.
The plain truth is that the best USA players, as a group, simply are not as good as the best players in other countries. This is true both in Olympic hockey and NHL hockey.