@asdf, missing out
"PowerPC wont die but at least it is largely gone from general computing."
But not gone from other fields. Sectors like telecoms, military computing, etc. tend to care less about architectural backwards compatibility and more about performance, power consumption, etc. By being willing to switch around a bit they can exploit whatever is best at the moment. PowerPC is in fine form in the telecoms world, but has slipped a bit in the high performance embedded world.
Whereas 'general computing' has been stuck in the Intel rut for decades now. The trouble is that the battery powered and server farm sectors of 'general computing' have already chosen ARM or are threatening to do so. Why is that relevant? Well, it signifies a greater willingness on the part of the vendors to look beyond the world of x86 for the performance that sells. Doing that once means they have to keep doing it should something better come along in order to retain a competitive edge. It's entirely possible that PowerPC will be the chip of choice, and it might not be too hard for some vendor to go for it. The trouble is that such an endeavour will always be commercially driven; an offer of cheaper Intel chips might be just as commcercially advantageous as switching to another architecture to get a performance edge.
ARM is having a quite interesting impact on the market. They own the mobile market, and they may end up owning the laptop market too (MS porting Windows, Apple talking about an ARM laptop). They may also end up owning a large chunk of the server market too if vendors see useful performance per Watt figures for ARM servers. So where would that leave the great big hulking chips that Intel and AMD are churning out? With a somewhat smaller market I would imagine, apart from the power Desktop users, and there's not really many of them. So will Intel/AMD keep developing these very powerful chips if the ARM architecture starts taking over the server market too? Possibly not, or not at the same pace.
So where might users who do actually need fast general purpose compute performance turn? With Freescale seemingly tarting up the PowerPC line with some recent anouncements and the embedded market there to support it, there might yet be a commercial rational to move high performance computing over to PowerPC. Adobe may yet have to dust off their old Photoshop source code. I can remember in the early days of Intel Macs Photoshop was slower than on the G5s because there was no altivec unit to exploit for all those image processing functions.
Regardless, it seems likely that the end users are going to have to get used to underlying architectures changing more than once every 20 years. We should be grateful. It'll mean more performance (hopefully) and less power consumption, and who cares what instruction set lies beneath?