You make some valid points regarding the time to move on factor, but once again, I've ALWAYS been arguing about G5's, both iMacs & Powermacs, all of which were 64bit, some of which had the capability to run really powerful graphics cards.
All of the Snow Leopard optimizations would benefit these machines. All of the BUG FIXES in Snow Leopard would benefit these machines. And all of the machines are capable of running Grand Central to some extent more so than the early INTEL graphics Macs are capable of running OpenCL.
These are just indisputable facts and go completely against what many of the PowerPC-haters here are ranting about.
I don't think anyone has ever suggested that Apple try to support G4 processors. I certainly haven't.
Steve Jobs and Apple during the INTEL announcement sort of made a commitment to support PowerPC to keep Apple sales going for about a year during the transition.
I think they broke that support commitment, maybe not legally, but certainly ethically.
Snow Leopard breaks an historically long Apple support model for Macs for a good portion of the Mac community.
And 2-3 years is bad support in my opinion.
Obviously, lots of people disagree, but almost ALL of them own INTEL Macs only, go figure! LOL