You've jumped to conclusions; no one is saying there's no one qualified in the U.S. As one of the links I posted mentions, many companies already have R&D in China, and there are many diff types of R&D. That doesn't mean Apple needs to move all operations there.
China is a huge market, but many people there can't afford Apple products. One of the advantages of R&D in a market you're trying to pursue is leveraging local talent, which better understands local needs. China also has a huge pool of people with strong math and science skills. And of course Chinese labor is cheaper; no one has said otherwise.
The U.S. still has some of the best universities in the world, which is why many foreigners, including Chinese, flock here for an education. But foreigners also helped build Silicon Valley -- Indians, especially. A mix of talent is better than homogeneity, esp if you want to sell to the world.
And techies are in high demand in the U.S. right now, despite the otherwise crap economy:
Surveys Show Tech Workers in Most Demand in 2013
There's actually a shortage of techies with certain skills. For instance, my husband has gotten about a dozen recruiting calls in the past few months. His company gave him a big raise and additional perks to stay, and they've got jobs they've been unable to fill because they can't find the right people. Among his colleagues: a big mix of talent from worldwide, including many from and in Asia.