Selling prices are arbitrary. A falling-apart, faded, brittle color cardboard collage by singed by Matisse or Picasso might sell for hundreds of thousands of dollars, while a masterpiece of solid hardwood furniture might sell for a tiny percent of that. Likewise, commercially printed color inkjet, outputted in multiples, in a rather mediocre frame from an Eggleston image might fetch $20,000 dollar in a gallery, while an absolutely exquisite handmade carbon print by an unknown might be lucky to fetch $200.
But in terms of the specific terminology, yes it does need to be addressed and defined in some consistent legal manner, so as to avoid misrepresentation. That is the standing policy in the States of NY and CA, for example, concerning selling lithographs. A real lithograph involves an inherently limited quantity due to the nature of the press medium itself - an etched copper sheet, or stone plate, etc, made by artist himself. But a photolithograph is something copied or scanned, and then outputted to offset reproduction, which can then crank out fancy posters in the tens of thousands if needed. Using the same term, "lithograph", for both categories is therefore illegal, since it has long been the basis for deceptive pricing to naive "investors", thinking that their $4,000 has been well spent for something that only took $4 to make, and that is worth far less than the frame itself the gallery displays it in.
In this case, an assumption is being made that there is some kind of absolute permanence to any image categorized as pigment. Well, every serious painter knows that not all pigments are created equal in that respect, and that most are not in fact indelible to UV. And in the case of inkjet inks, just a little study of the underlying patents will show that they are complex blends of fine pigments, rather typical photo dyes, and lakes (dyed inert pigment particles), and therefore themselves a mixed bag.
