When I can print my own aftermarket auto parts out of better materials (I.E. - make my own stainless steel radiator instead of crappy ones they make now with crappy plastic side tanks and crappy plastic threads on the drain valve). Now that would be something.
It's funny to me that they're called "3D printers" when the machine has a lot more in common with a CNC than a printer.
I think they technically are CNC's, though the traditional understanding of CNC is to create the part by removing material rather than adding it. You can buy regular metal CNC's for home use (even to make radiator parts!). They were not incredibly expensive the last time I looked.
Maybe the term "3D printer" makes it seem a lot more accessible to normal "non-shop" people. I dunno, I'm not a machinist but not scared of whirring motors and drill bits either.
This could very well be true. If manufacturing becomes something you can do at home just like desktop publishing in the Internet Age, then this will greatly affect the trade balance and the consumer's reliance on corporations. It will shake things up quite a bit. As such, the real consequences are unpredictable.