Tom Easton blogs about how 3D printing could potentially be very disruptive to industry, specifically by disturbing traditional business models when vast amounts of items are printed at home instead of sold in stores (online or offline). Apparently he's considering writing a book on the topic.
I agree with this premise; we will likely see significant disruption to the manufacturing industry just as we saw the photo industry change in recent years. But like the photo industry, manufacturing will have to do the same sort of things - provide new media, devices and a new category: pre-made designs, suitable for printing. It's not going to be bad news for all. It will be a tremendous opportunity as well.