That is a common and completely incorrect belief.
The great majority of the iPhone's economic value goes to the US.
Here is the iPhone 5's bill of materials.
Groundbreaking iPhone 5s Carries $199 BOM and Manufacturing Cost, IHS Teardown Reveals - IHS Technology
Of the $750 price of the phone, $550 is profit for Apple, that pays for its employees who are overwhelmingly in the US.
$200 goes to various makers of semiconductors and other components. Almost all of those are made in semiconductor fabs in Taiwan (TSMC etc) or Korea (Samsung etc) with package/ test done in various countries including China. Roughly half of those chips are sold by US semiconductor companies (Qualcomm, Broadcom, Cerus, etc) so their profit margin (60% or so) goes to pay for their mostly-US employees. The battery, case, and a few minor chips are from China.
$7 is the packaging and the accessories in the box (AC adapter, earbuds, cable). That comes from China.
Assembly is $8. That is done in China.
So basically, about 70-75% of an iPhone's value flows to the US, about 5-10% to China, the rest to Taiwan and Korea.
The iPhone is awesome for the US. We need more products like that, not fewer.