Keith,
I have a print hanging on my wall (which sees open shade daylight and fluorescent indoor light) since it was printed 7 years ago by an Epson 890 (read as: lamest dye inks) that shows no signs of fading whereas I have prints that show silvering after 4 years (made by friends, and yes I know it's a processing error)... Now, probably the print has changed somehow and I could see the difference if I were printing a new one today, but if that simple cheap dye inkset can hold that much I can use what current high-tech pigment based inks with pleasure and confidence. If I cared for a print with a certain life expectancy >100 years, I mean if I was in real need of it, I would print it in gum, carbon, cyanotype, pt/pd or you name it (but not silver based and untoned)...
As for inkjet prints against "traditional" prints; I think we'll see that figures for inkjet prints when they will become "traditional" (or as a better / more correct term: "vintage")... How much Andreas Gursky's huge C-prints fetch right now? (Maybe he does inkjet also...) Are C-prints ("dyes" in gelatin on "synthetic" substrate to my knowing) indeed more archival than current high tech inkjet inks (pigment trapped in paper fibers) on matte paper? How are c-prints made today? (Especially wall sized ones...) Do buyers pay six figure sums to photos solely because they're traditional hand made prints, or do they have other incentives?... ... ... (a thousand questions more; you got the idea...)
And please, don't get me wrong. I'm in favor of neither and also I'm in favor of each. I do both, choose the method according to when it's appropriate to my purpose / convenience / my current masochism level.
Regards,
Loris.
P.S. Won't pursue since we're way out of topic + subject goes to way inappropriate areas for this site...