This doesn't surprise me too much. Any company like Apple would have to keep its options open. Until you announce a decision to the world, you explore alternatives, just in case the one you're thinking of doesn't turn out like you planned. So I'm not surprised that Apple was seen "courting" alternative PPC manufacturers.
But, based on the description of PA Semi's products, they only sell G4-class chips. I didn't see any mention of 64-bit capability, which would mean the PowerMac line remains stagnant (or ends up needing ever-larger power supplies to drive the newest IBM offerings.) A quad G5 today uses a 1KW power supply! This is insane, and everybody knows it.
As for IBM, they gave Apple the finger several years ago. They want Apple to directly fund their own R&D efforts, or there won't be any new G5-class chips. Call me crazy, but if I'm going to fund someone else's R&D, I'd better become an owner of that tech, not just a customer. Somehow, I don't think IBM would be willing to start giving Apple royalties for PPC chips manufactured.
As for the newer gaming chips that IBM's working on (like Cell and others), read the specs. They're not powerful enough for general purpose computing. They are relatively low-powered CPUs, with large numbers of independent vector processing units. This may be fine for games or rendering pipelines, or even GPUs, but it is terrible for other kinds of applications. How many Macs would you be able to sell if productivity apps (word processors, spreadsheets, databases, web browsers, mail clients, etc.) run at half speed? Telling them "but Motion is 5 times faster" isn't going to help.
If PA Semi had a tighter roadmap (get the newest chips out sooner), and a 64-bit products ready to go, things might've been different. But that didn't happen.