I'm not sure you could say they fully transitioned from PPC to PPC64, as only the G5s were 64bit, and laptops never got the G5. I think the x86 transition would

I'm not sure you could say they fully transitioned from PPC to PPC64, as only the G5s were 64bit, and laptops never got the G5. I think the x86 transition would have been easier if it started out 64bit, but that's probably Intel's fault. More practically, the transitions so far have been like this: 68k -> PPC (With full 68k emulation) -> x86 (with partial PPC emulation) -> x86_64