Here's an excerpt from the Apple article:

Though components differ between versions, all iPhones contain hundreds of parts, an estimated 90 percent of which are manufactured abroad. Advanced semiconductors have come from Germany and Taiwan, memory from Korea and Japan, display panels and circuitry from Korea and Taiwan, chipsets from Europe and rare metals from Africa and Asia. And all of it is put together in China.

In its early days, Apple usually didn't look beyond its own backyard for manufacturing solutions. A few years after Apple began building the Macintosh in 1983, for instance, Mr. Jobs bragged that it was "a machine that is made in America." In 1990, while Mr. Jobs was running NeXT, which was eventually bought by Apple, the executive told a reporter that "I'm as proud of the factory as I am of the computer."As late as 2002, top Apple executives occasionally drove two hours northeast of their headquarters to visit the company's iMac plant in Elk Grove, Calif.

But by 2004, Apple had largely turned to foreign manufacturing. Guiding that decision was Apple's operations expert, Timothy D. Cook, who replaced Mr. Jobs as chief executive last August, six weeks before Mr. Jobs's death. Most other American electronics companies had already gone abroad, and Apple, which at the time was struggling, felt it had to grasp every advantage.

In part, Asia was attractive because the semiskilled workers there were cheaper. But that wasn't driving Apple. For technology companies, the cost of labor is minimal compared with the expense of buying parts and managing supply chains that bring together components and services from hundreds of companies.

For Mr. Cook, the focus on Asia "came down to two things," said one former high-ranking Apple executive. Factories in Asia "can scale up and down faster" and "Asian supply chains have surpassed what's in the U.S." The result is that "we can't compete at this point," the executive said.

… "The entire supply chain is in China now," said another former high-ranking Apple executive. "You need a thousand rubber gaskets? That's the factory next door. You need a million screws? That factory is a block away. You need that screw made a little bit different? It will take three hours."

… "They could hire 3,000 people overnight," said Jennifer Rigoni, who was Apple's worldwide supply demand manager until 2010, but declined to discuss specifics of her work. "What U.S. plant can find 3,000 people overnight and convince them to live in dorms?"

…Another critical advantage for Apple was that China provided engineers at a scale the United States could not match. Apple's executives had estimated that about 8,700 industrial engineers were needed to oversee and guide the 200,000 assembly-line workers eventually involved in manufacturing iPhones. The company's analysts had forecast it would take as long as nine months to find that many qualified engineers in the United States.

In China, it took 15 days.

Companies like Apple "say the challenge in setting up U.S. plants is finding a technical work force," said Martin Schmidt, associate provost at the Massachusetts Institute of Technology. In particular, companies say they need engineers with more than high school, but not necessarily a bachelor's degree. Americans at that skill level are hard to find, executives contend. "They're good jobs, but the country doesn't have enough to feed the demand," Mr. Schmidt said.

Some aspects of the iPhone are uniquely American. The device's software, for instance, and its innovative marketing campaigns were largely created in the United States. Apple recently built a $500 million data center in North Carolina. Crucial semiconductors inside the iPhone 4 and 4S are manufactured in an Austin, Tex., factory by Samsung, of South Korea.

But even those facilities are not enormous sources of jobs. Apple's North Carolina center, for instance, has only 100 full-time employees. The Samsung plant has an estimated 2,400 workers.

"If you scale up from selling one million phones to 30 million phones, you don't really need more programmers," said Jean-Louis Gassée, who oversaw product development and marketing for Apple until he left in 1990. "All these new companies — Facebook, Google, Twitter — benefit from this. They grow, but they don't really need to hire much."

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