Ok, it sounds like an obvious question, but Apple didn't always do their manufacturing overseas. The NYT explains how the manufacturing game changed.
"In 2007, a little over a month before the iPhone was scheduled to appear in stores, Mr. Jobs beckoned a handful of lieutenants into an office. For weeks, he had been carrying a prototype of the device in his pocket.
Mr. Jobs angrily held up his iPhone, angling it so everyone could see the dozens of tiny scratches marring its plastic screen, according to someone who attended the meeting. He then pulled his keys from his jeans.
People will carry this phone in their pocket, he said. People also carry their keys in their pocket. “I won’t sell a product that gets scratched,” he said tensely. The only solution was using unscratchable glass instead. “I want a glass screen, and I want it perfect in six weeks.”
After one executive left that meeting, he booked a flight to Shenzhen, China. If Mr. Jobs wanted perfect, there was nowhere else to go."
http://www.nytimes.com/2012/01/22/business/apple-america-and-a-squeezed-middle-class.html?ref=general&src=me&pagewanted=all
