Are you kidding? It seems as though you're defining efficiency as producing the item for the lowest cost to the manufacturer. How they accomplish that is the whole question. So let's see ... how do the Chinese accomplish that "efficiency"? (Hint: think about the highest cost to virtually all employers.)
I know what you are saying Munji...I just didn't want to derail from the OP...too much.
The efficiencies are largely human, this is obvious. For sake of argument, the 24 hour a day factories are filled with people that want to work, are happy to work, and generally speaking in good conditions. I know they can be precise when asked, they make a lot of our optics for camera's, rifle scopes, etc
I have many colleagues that regularly visit the Asian factory's. China for better or worse doesn't have to deal with the liability and insurance complications. Like the US factory's the people that are attracted to working at a musical instrument factory are the same kind of people. The environment is better than walking through the city and because they have to remain competitive, dust control is top notch.