I love the idea of 3D modeling and rapid prototyping for product generation. I spent an afternoon checking out machines & prices to see if one of these things could be gotten hold of by the common man. There is a desk top machine in development out there. Part quality (smooth surfaces) is a bit of a concern but if modelings first chore became a technique to account for this it would not be too bad.
The thing I do not like in your outline is the comparison to music. Sharing specifically. If a 3D modeler were to spend 100 hours (probably a lot more) on a design that is sold electronically, the potential to share that file is not only possible but likely. There is no benefit to the design originator to enter into such an agreement. Music is different (only slightly) in that the group is looking to build fan base as well as unit sales. By giving into the sharing mentality(loss of unit sales) they are taking a leap of faith that overall it will result in a stronger fan base that will in-turn support them in a monetary fashion. Just not by todays youth that think music should be free, fame is the bands reward and money is something they just have.
Maybe I have taken this wrong, perhaps the intent is to have the electronic file shared among specific 3D printers to control the 3D modelers intellectual property.
Rapid prototyping is very cool though and I do believe it will find a place in the hobby room in not too many years. I struggle to see it as a full on replacement for volume production though.