The heck it wasn't
From page one:
The president’s question touched upon a central conviction at Apple. It isn’t just that workers are cheaper abroad. Rather, Apple’s executives believe the vast scale of overseas factories as well as the flexibility, diligence and industrial skills of foreign workers have so outpaced their American counterparts that “Made in the U.S.A.” is no longer a viable option for most Apple products.
iPhone screens required finding an empty cutting plant, hundreds of pieces of glass to use in experiments and an army of midlevel engineers.
The owners made engineers available at almost no cost.
Gee, how were they able to do that?