an alternative perspective...
You know, if you think about this, just for a second, there are some facts staring us in the face.
(1) Motorola's semiconductor division has been losing money for a long time now.
(2) Motorola and Apple have a known public rift (over cloning), and Motorola has dropped the ball on development of newer, faster chips.
(3) Motorola hasn't made an announcement about anything dealing with desktop PowerPCs for months.
To me, this all adds up to Motorola no longer being involved actively in PowerPC development. It tells me they are just fulfilling their contracts with Apple.
If that's true, it would seem to me that the desktop chip market is something Motorola would gladly just shut down, in order to consolidate their efforts toward the embedded market, and save money.
It's also been *rumored* that Apple has (of late) taken a much more proactive effort in chip development (previously, under the AIM consortium, this was left to IBM and Motorola, and Apple concentrated more on the software).
Anyway, what I conclude from all this is that Apple has bought Motorola's intellectual property related to PowerPC. That would explain how IBM was able to develop an AltiVec clone without violating Motorola patents.
If you accept that conclusion, then you realise there's a missing piece in the PowerPC alliance. I think, for Apple's sake, it makes sense to have two different PowerPC suppliers, and two different companies contributing ideas to the PowerPC architecture.
So, could AIM simply become AIA? In other words, why not consider AMD as the new third partner in the PowerPC consortium?
That would certainly qualify as a "shattering" development, and it doesn't fly in the face of logic quite as much as Apple releasing X86 boxes. Sorry, that makes absolutely no sense with 970s on the way; Apple's just not ready for that kind of a paradigm shift right now.