Apple gets an average selling price of around $600 for Iphones. This leaves some margin for retailers. The $48 per phone you cited results in a net margin drop of around 8%. That's a massive hit to margins. And that's assuming that stateside assembly workers would be content with minimum wage jobs (Chinese workers were making $1.78/hr in 2013). My suspicion is that Apple assembly lines stateside would be unionized and cost $16 per labor hour, without even factoring in the generous benefits that Foxconn, Apple's Taiwanese subcontractor, doesn't pay to its Chinese workers. That would mean a net margin reduction of 18%. What manufacturer would give up 18% of margin to manufacture stateside? What happens when its hot product turns ice-cold? Apple products would have 18% less net margin with which to fight a price war with its competitors.
But, going back to the original poster's point, which was that outsourcing to China was suicidal, I can't say that's clear from the historical record. All of Lumber Liquidators' competitors source from China. They just do a better job of either choosing or auditing their suppliers.
The thing with Chinese suppliers is that they sell to the world. Less-developed countries have fewer regulatory requirements. We stopped allowing lead paint on toys starting in the 1970's. Plenty of countries around the world have no problem with lead paint on toys. We sent a man to the moon in the late 60's, despite have lead paint on toys while NASA researchers were growing up during the interwar era. Since then, we've had two Space Shuttle explosions, and the shuttering of the manned space program. Maybe we need to put lead paint back on those toys.
Karl Marx was a big fan of ‘Free trade” too.