Ugh, that's what I get for not doing research before I post. I thought their POWER machines were now pretty much limited to server duty. My mistake. Still, IBM is no longer a PC manufacturer any more, and those workstations are not something an individual is really going to have a use for/ability to practically use it.
Compatibility. Intel just got big over the years and everyone wrote for their architecture.
That, and the acceleration of 3D graphics on PCs--all manner of specialized applications used to be only doable on specialized workstations until good OpenGL support showed up on PCs. My personal example is CATIA, since my work has led me there many times; as recent as V4 (used by Boeing to design the 777), there was no Windows version, only UNIX and IBM mainframe. By V5, mainstream hardware running on far-cheaper Windows-based machines (still more than a cheap mail-order Dell, but in the 1-3K range instead of double or triple that) could do the same work, and Windows support was justifiable. All of the sudden, demand for those specialized IBM, Sun, and SGI boxes plummeted in the industry (and likely beyond, but I can't speak with any authority there). Heck, for V6, UNIX support is gone, altogether. That pretty much speaks for itself. (To put this in perspective, each major version of CATIA is a big deal; seats for that program are generally in the $20k range, and can go up from there)
