I loved the PowerPC chips, the 604 and G5 in particular. Too bad it never became a viable platform outside of Apple.
(In the '90s, the PowerPC had very competitive price/performance, but there wasn't a viable desktop OS available after Apple terminated the original MacOS clone program. 5-10 years later Linux would have been much more ready, but the chips were not competitive with Intel anymore.)
I can't help wonder if Intel "won" by bruteforcing the lithography side. But this then made them "blind" to the reduced cost side of Moore's Law (or they tried for the longest time to get people to ignore it).
Their first reminder was perhaps netbooks, using semi-retired Celerons to make small and cheap clamshell web browsers and media players.
Their second, and ongoing, reminder is smartphones/tablets.
PowerPC essentially died as a desktop and server processor once Apple decided to go Intel. IBM decided to go back towards Power's roots with the POWER5 (the follow-on to the PPC970 in the Power Mac G5 and the PowerPC-based XServes).
PowerPC really died in 1997-98 when it became clear that Jobs wasn't going to license Mac OS (classic or X) for 3rd party PowerPC boxes anymore, and Windows NT on PPC wasn't going anywhere.
Without an operating system, IBM and Motorola didn't have an incentive to build PC chips anymore. The G4 happened because it was already in development and the vector extensions were useful for Motorola's embedded ambitions. The G5 happened because Apple basically paid IBM to make a desktop chip out of their POWER designs, AFAIK.
Around 2004, there was a startup PowerPC maker called P.A. Semi [1] that apparently competed for Apple's Mac CPU business. After Apple went Intel, they acquired P.A. Semi to design iPhone chips instead.
For large swaths of life the PowerPCs in a mac significantly faster than any available x86 CPUs. Back in the single core days, clock speed was something that lay user vaguely understood was correlated to performance. This had a subtle but real impact as Intel and OEMs were effective in marketing clock speed number as something users should care about. It was very effective until it backfired when AMD torpedoed intel with Opteron, and then clock frequency scaling became undesirable.
The idea that PPC was faster than x86 back in the PPC mac days is Apple hyperbole. There were a few occasions where the fastest PPC was faster than the fastest x86 available but they were far and few between and very slim. If all you looked at were the very carefully selected/tuned apple benchmarks you can be forgiven for thinking that (the photoshop filter benchmark using altivec comes to mind) there was a huge PPC advantage.
Here is a random google search for spec performance over time of assorted CPU arches.
The only obvious case in that graph where PPC>x86 is in mid 1995.
I can't find the one I saw a couple years ago detailing the core/clockrate comparisons of PPC's shipped in Macs with common PCs, that was much easier to read and far more obvious.
It wasn't just Apple hyperbole, PowerPC really did beat Intel at quite a few instances, and generally kept up until about 2004. AltiVec with photoshop was not just a tuned benchmark but a significant advantage on a common scenario. The Power chips also consumed significantly less power, enabling Apple to put far more powerful CPU's in laptops.
(It always confused me that my PowerPC 603 @ 75 MHz (a Performa 6200) was so, so much slower than my PowerPC 601 @ 80 MHz (a Power Macintosh 8100) – it wasn't until years later that I learned that the '601 was executing three instructions per Hz whilst the '603 was only executing two instructions per Hz...)
(In the '90s, the PowerPC had very competitive price/performance, but there wasn't a viable desktop OS available after Apple terminated the original MacOS clone program. 5-10 years later Linux would have been much more ready, but the chips were not competitive with Intel anymore.)