Apple manufactures their products in China because they get most of their components from Asia, and because they sell most of their products in Asia, too.
That last item is something Americans may never get used to. We always like to think of ourselves as richest country in the world, but as consumer products become more affordable the value of 300+ million customers in the U.S. starts to diminish compared to a billion customers in China and another billion in India.
As soon as China makes a move militarily, there will be zero products coming to America from the land of the suicidal factory coolie. They are not stupid enough yet, but they are getting there.