There's also an implicit assumption here that the design of objects will not change to support their production method. So, if we're limited by size or number of materials then designers will adapt to those constraints.
Currently the number of materials you'd need to stock in your home to be able to print various kinds of products would be quite large (20 or more). That doesn't make sense from an economic perspective.
Let's image, then, that we'll see products made from fewer raw materials because the design changes to accomodate printers. What reason would designers/manufacturers have to do that when they know they won't be able to make a living when their products get pirated?
> What reason would designers/manufacturers have to do that when they know they won't be able to make a living when their products get pirated?
The same reasons people still write software and make music, even though they know their products get pirated - you can still make money from it. I agree though, it will be a completely disruptive innovation from the point of view of designers and manufacturers.