I don't see a long goodbye, I see no goobye at all. In my opinion, x86 desktop share by the end of 2005 will not be different from today at all. If it ever starts losing, that will happens no less than 4-5 years from now. And the replacement will never be the IPF, it will be scaled up ARM instruction set.
Today's pocket organizers (Palm and PocketPC) have 128 Meg of ram, up to 2 Gig of storage and over 400 Mhz cpu. This is just 3-4 years behind the desktop. I already saw the 640x480 3" screen for the pocket organiser. This is what is going next, not IPF. I don't know where IPF is going besides Alpha and HP-RISC replacements.