why buy a $550 CPU and motherboard for the PPC architecture, a $50 case, a hard drive, a keyboard, a mouse, and a CD-ROM drive
Maybe it could be because some of us like to support alternatives and see their importance in keeping the marketplace diverse? You know, all that silly "ensuring through our choices today that we will continue to have a choice in the future" and other such rot.

Of course this sort of thing doesn't matter to the typical consumer, for whom all decisions are made within a purely immediate context. (I only buy what is biggest/best and costs the least, and I want it THIS INSTANT!) Move along now, nothing to see here.