Americans already make cars. Even "Japanese" (Honda, Toyota) cars sold in the US are usually made in the US.
iPhones and other smartphones being made here will probably up the prices slightly, but most of the estimates I've heard are absurd.
iPhones could be made completely in the US and Apple could charge the exact same price for them as they do now and the only difference is Apple's profits would go from ridiculously obscene to only slightly obscene.
But where (in the USA) would you make them? Industry is "dirty"... we only do clean businesses.... like McDonalds.