My prediction:
The 3D printer market will implode once people start using 3D Printers to pirate 3D Printers, eliminating all sales and driving the manufacturers out of business.
All we'll have left are copies of copies of copies of printers, which will eventually cease to function correctly.
I kid of course, but the ramifications for intellectual property are staggering, and I don't know how you deal with them. How can Lego, as one simple example, possibly hope to survive in a world with pervasive 3D printer access?