And one that's usually not done by Apple or Samsung, but by contract-manufacturers like Foxconn. Both Apple and Samsung use Foxconn. The "iphone factories" aren't Apple-factories, they're Foxconn factories which currently produce iphones but will produce Samsung galaxy phones if iphone production moves.

It's a "companies use Chinese as-close-to-slave-labor-as-you-can-get-without-being-called-out-labor" thing, not a "naive Western company finds out how things work in China" thing.