I think a lot of the costs of PPC can be blamed on Apple/IBM. If the fruit hadn't dropped PPC, then they'd most likely be a bit more 'commodity' than they are now. IBM and some embedded systems are really the only ones using the architecture anymore.
As much as I think it'd be cool to own a PPC, my thoughts are this;
With a 68060 (which I now have, though it's at 50mhz and I'd really like to overclock it, but no one has overclocked a Cyberstorm MK I that I know of) you get the old classic feeling of the Amiga on real hardware. There isn't a whole lot of PPC only software out there unless you run AmigaOS4.x And Once you go with 4.x or MorphOS or AROS, then you're pretty much in emulation land for 68k software. In which case I have a big beefy system with Arch Linux, Debian GNU/Linux and Windows 7 on it. So I could emulate and / or use AROS. This system costs less than that crazy ass posting of an accelerator.
So while the geek in me thinks "Hell yeah, gimme, I still want a PPC, because I've never owned one!", the realist in me thinks "would it be useful for anything besides saying "I have a PPC bitches!"?
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