I see 3-D printing as just one small area in the ever expanding world of technology. A lathe was needed to make the printer nozzle. Microcode and computers on a chip to control it. Hobbyist and robotics fan-boy websites, as well as thousands of youtube videos reveal amazing things people do in their garages and dens. 3-D printing is sort of an adjustable wrench in the larger scheme, as amazing as the milling machine or silicon lithography when they first came out.
Printer nozzles can be printed. Just like I can build another lathe with my existing lathe. But you have to have the first one.
/johnny