Unfortunately my sense is that even Foxconn pay and conditions are far superior to anything available for these workers in their usually rural home towns.

Take it another step. Dreadful conditions are allowed to fester due to a lack of human rights in China, which is maintained as a status quo solely because shareholders in western companies demand infinite growth and profit. These companies came to Chinese factory owners with a price for labor already in mind; they would have payed to move production to anywhere in the world with the lowest costs for labor and material acquisition.

Better labor conditions in China starts with western companies requiring better labor conditions to do business, and western companies accepting the resulting higher costs. Until shareholders accept smaller profits, this won't change no matter where in the world it occurs.