American only care if their players dominated the sport. It's too bad that other countries have caught up and surpassed them, just like Australian use to dominate the sport but now have to take the back seat. The US has to put much more of an effort than in the 80s and 90s in order to have a great players like Sampras or McEnroe. In fact, every countries has to continuously improve or else they will be out of the picture.
Tier1(goat): Federer; Tier 1.5: Laver, Gonzales, Sampras, Nadal, Borg;
Tier 2: Lendl, Connors, Rosewall, Tilden; Tier 2.5: McEnroe, Agassi