What people sell in Northamerica, whether in fast foods or restaurants, is not pizza. It's a surrogate. It's a lookalike, made with different ingredients, different preparation methods, and ends up tasting quite differently from the real thing... I have yet to find one single place that tastes the way it should. Just change the name, it'd be the decent thing to do.
Try and go to any standard pizzeria in Italy or surroundings, and you should be able to taste the difference.
Or then again, maybe not - after all people call Budweiser "beer", even though it's made with 30% rice... but it's still less different from a pilsner than the so-called "american pizza" is far away from the real thing.