In the latter days of the PowerPC, development had clearly stalled. Although you could buy a Power Macintosh G5, a forerunner of the Mac Pro workstation, there was no similarly outfitted notebook. PowerBooks were still saddled with the G4 The reason? IBM and Motorola were not able to tame the beast to work within the constraints of a mobile device, or perhaps they didn’t care.
Indeed, some Power Mac G5 configurations required liquid cooling, and even with just fans, the system required several operating in an extremely sophisticated environment to keep the units from overheating. If the coolant leaked, your computer was toast.
At the time, Steve Jobs told interviewers that he was pleased with IBM’s PowerPC product roadmap, but that Apple was always considering its options. A key problem was the fact that other computer makers weren’t using PowerPC chips, which became more popular in the embedded market. So there wasn’t much incentive to deliver the parts Apple needed.