Rather, you mean that PC laptops "have never been upgradable (save for memory/HD." PowerBooks (not all models, naturally) have been quite upgradable- with some you can upgrade processors and video chipset. One model of 68k powerbook you could upgrade to a zippy (at the time) PPC proc. Also, I believe with newer PowerBooks you can get a PCI breakout box.
Re:They really don't need to "support" an OS (Score:2)