I think when 3D printing takes off it will be the intellectual property where the money is at. Industrial infrastructure (ie. factories, logistics, etc) will become just another commodity like computing hardware is now. China will be the industrial giant no more if it continues to rely on its manufacturing industries and doesn't adapt.
What about when 3D printers are printing buildings, bridges and other structures? Wow that would be amazing.
Thats already the reason for China - injection moulding is very cheap (once you have made the mould) and commodotized.
It's assembling and packaging the parts that takes a lot of time/labor. It's the low labor cost of assembly that is the reason for China - a million 3d fab machines replacing a few injection moulders isn't going to change the time it takes to put the bits in boxes.
What about when 3D printers are printing buildings, bridges and other structures? Wow that would be amazing.