"But what if you like the look or the capabilities of a newer medium?"
I agree Paul. Kirk Gittings has mentioned on another thread how he wishes he'd done all the prints for his recent show using the new Epson and K3 inkset. He likes the color better. And he likes the look of the B&W on matte paper as much or more than his silver output.
I think we are seeing a shift away from some of the analog processes to the new digital ones. Much in the same way that silver replaced pt/pd prints of old for those who wished to avoid the un-natural brownish to bluish tones. It's good to question the permanence of inkjet prints. Now that much research has been done over the last few years, even if the stated 200-300 years for B&W inkjet behind UV glass is cut in half, I think 100-150 years is still adequate. I see no reason to question the inkjet permanence tests and not those of silver or other methods. This is even more so considering that a lot of the silver and color prints done over the last 50 years show fading as well. This isn't even going into what a lot of color negs look like from the 50-70's.
In the end, if you've got a beautiful photo, printed with carbon pigment ink, on a high quality paper like Hahnemuhle, you should be good for generations to come.