I would like to offer a couple of points here: When the Intel machines first came out, the highest quad PPC Mac Pro was still the most powerful machine around and for a while. Additionally, Apple had heavily advertized its 64-bit processing capability boasting about the computer's potential longevity, addressing professionals obviously and not just Internet surfers and Word users.Therefore, as consumers, I don't think we should be taking alleged technological obsolescence for granted. Four years is not enough usage for what would have been then a ca.€5000 machine (including extra RAM and ROM). Clock speeds have not advanced that much since, plus that computer's 64-bit capability would render it much faster than it used to be, and if not state-of-the-art, still a very viable solution for modern standards of work. I stand to be corrected (BUS speeds, cache, etc.), but I mean this post as a more general comment on consumer attitudes towards technology-companies. For my money, €5000 is way too much to be parked on a bulky machine for just Farcebook and games usage, even if someone has already made that money twice over by using it professionally.
Finally and lightheartedly, lest we forget, it is still the only powerful machine that can still run OS 9.x, which I still love (despite its Extensions nightmares).