Remember this quote by Steve Jobs:
"Now, as you point out, once our transition to Mac OS 10 is complete, which I expect will be around the end of this year or sometime early next year and we get the top 20% of our installed base running 10, and I think the next 20 will come very rapidly after that. Then we'll have options, and we like to have options. But right now, between Motorola and IBM, the roadmap looks pretty decent."
He seems to be hinting at two things here: first, dropping OS 9 support and second, introducing new architecture(s), made possible by going fully OS X. And even though it's ambiguous, he seems fairly comfortable with staying with the PPC for a while. (that means no to OS X on Intel)
He makes the point of mentioning both Moto and IBM so IBM will obviously play a big role in the future, and we know that's not going to be with G3s.
"The roadmap on the PowerPC actually looks pretty good and there are some advantages to it. As an example, the PowerPC has something in it called AltiVec, we call the Velocity Engine -- it's a vector engine -- it dramatically accelerates media, much better than, as an example, the Intel processors or the AMD processors... so we actually eke out a fair amount of performance from these things when all is said and done."
Yeah, Altivec is here to stay. IBM must be licensing it from Moto. Or maybe Apple bought out the PPC assets from Moto. It's one aspect of the G4 that really shines. So it's good to see Apple keeping it around and committing to it more. Hopefully developers are hearing this and following suit.