Boycotts can work a little, but a boycott large enough to be effective and overcome other market forces is very hard to organize and sustain.

I'm not totally letting Apple off the hook, just pointing out that without the government doing something here any measures Apple or anyone else takes will be ineffective. Even if Apple starts pushing back on this, other manufacturers will fill the void and take advantage of that cheap labor instead. Apple might even find it tough to police this since Chinese companies may lie about where work is being performed or who is doing it. They're likely to demand that Apple pay more for different labor and then pocket the money and use forced labor instead.