- Dig it out of the ground
- process it
- Fabricate the unprintable bits
- Store all of this
- Print whatever the consumer needs in less time than it takes to drink a coffee.
So unless this make believe "shop" is fronted onto a processing/fabrication plant, which is itself, fronted on a magical mine that you can dig up any resource you like. Your scenario can never happen.*
* Or we could invent teleportation.
Yes, there's a ton of raw resource extraction, processing, and transport.
But no, because a Nissan Altima or Apple Macbook (or Moto X!) are not commodities in the same way that gold or lumber or silicon are.
There's a reason that the Nissan Altima was the sixth best-selling car last year. I don't purport to know what that reason is, but it's not because it's comprised of raw materials any different from any other car.
http://reprap.org/wiki/MetalicaRap
http://medtechinsider.com/archives/24967
http://www.nthdegreetech.com/printed-semiconductors.php
That said, there will always be some things for which economies of scale win out against customisation, and I suspect that many electronics components are in that bracket. Luckily we have things like FPGAs, so you don't need to keep a huge stock of specialised chips to make a wide variety of devices.
FPGA's are several orders of magnitude more expensive than mass-produced electronics.
Modern cars contain more than just controller electronics. What about image sensors, for instance, for automated parking systems? You can't 3D-print an image sensor. Not without a clean room at least.
Is the same as keeping stock for a normal shop, you keep track of what is being used and order more when it gets low.
Even if China doesn't "lag behind" in the adoption of 3D printing, it will only be an advantage to them if they are significantly ahead. If you have similar-capacity 3D printers with similar operational costs in China and the US, US companies producing for the domestic market will still prefer to use the US ones to take advantage of the shorter supply chain. Chinese companies will prefer to use Chinese printers for the same reason.