Costco had been importing gray market watches from Europe, and selling them in the United States for nearly half the retail price encouraged through the watch maker's US arm. They sued Costco for copyright infringement, as the watches they sold in the US bore a different (and tiny) mark on the case, and the ones Costco were selling didn't bear that same exact mark.
Apple is doing the same thing. US market iItems bear marks that are slightly different than the marks on products sold overseas. More significantly, however, is the ability to instantly add a particular mark for the US market, and through this, they have the ability to ensure that no distribution chain OTHER than Apple can sell iProducts in the US, as well as setting specific requirements on their retailers including minimum price floors.
It is why Nintendo isn't made here, why XBox isn't made here, why virtually every popular consumer product isn't made here - so that there is no ability for an open, free and competitive market to pressure the company into lowering prices.
No tech company is coming back to the United States until the First Purchase doctrine is applied to ALL products, manufactured in or outside the United States.