Out of curiosity - does Foxconn procure the parts which it uses to assemble iPhones, iPads etc, or is it Apple's responsibility/domain to procure all the parts, with Foxconn merely putting it all together?
Apple produces the CPU, procures the screen, the aluminum, the glass, the memory and the glue. At the scale they operate, if they didn't, they won't be able to keep the production pipeline running.