Lets face it copyright, especially internationally, is a mess. So let us scope this so that anybody can answer about any region, but only one region per answer. Also let us keep the discussion in goods that clearly at some point lost the copyright, because prints and artworks really do not lose the copyright.
So how exactly do i know where the borders of copyright are. Generally, physical goods, like a chair or fashion has no copyright*. But then computer programs have a copyright. This is where it gets really wild.
Modern physical goods exist as digital models before they exist as reality, this model just like any other program created by human. Does the model enjoy copyright? Does the 2D drawing that is made form this model enjoy copyright? Does the CNC control code that produces the model (it is computer generated) enjoy copyright? The resulting object does not enjoy copyright!
At what point did it lose the copyright. If i scan the product and recreate a model. Did i strip copyright? If instead of scanning i read the position of the print nozzle or mill head to create a new toolpath?
Simply how does one know where the copyright ends. Because clearly for the chair to not have copyright protection it must end somewhere.
* Although they can have if they are deemed art. The question becomes easy if the object has copyright through its entire life. But not all things are like that, i am not interested in objects of this kind.