Economic efficiency has nothing to do with how the surplus is divided between parties. Powerful entities such as corporations can easily get most of the surplus

Economic efficiency has nothing to do with how the surplus is divided between parties. Powerful entities such as corporations can easily get most of the surplus their employees produce, and the market will not correct this. (I.e., you have no economical argument that non-protection of labor is needed for cheap commodities. Perhaps such an argument can be made, but yours doesn't cut it.)