They used to work that way in the US! Then came the labor protections.

Labor conditions are a prisoners dilemma. Individuals in a location can’t really choose to opt out of poor labor conditions if that is what exists there. That is why it took a lot of activism in America to change the labor conditions.

So right now we are exploiting people in places that don’t have the same protections. The comparative advantage of those places is in allowing suffering, not in the people actually being more okay with the conditions.