Yes, that being that Motorola then IBM could not compete in either performance or cost with the relentless advances being made over on the intel side. Intel macs didn't just appear; intel builds of OSX are as old as their PPC counterparts, just kept under wraps for several years. Apple could see the writing on the wall for desktop PPC way back then and wanted to make sure they had a clean exit strategy. Apple stuck with PPC for as long as it was feasible and not a second longer. If anything, given hindsight, I am a bit surprised they never jumped sooner, considering they already had the OS ready.
I thought I would quickly add my thoughts here... Apple is a
VERY "conservative" (small c) company... They will make a massive leap from time to time, but always with that leap they will ensure that they have the bare minimum feature set that works
PERFECTLY. Then they will add the bare minimum features every product cycle refresh, again making sure that the added feature set is working bang on... so while it look like Apple is jumping ahead, in reality they are making much smaller but far more sure-footed steps that they know will connect. This looks good to the general public who only want to see only confident, good steps...
I think this covers the intel transition, the G5 and G4 were both just about holding their own in 2005, and this gave Apple time to really polish the x86 port of OSX and give intel time to get the new Core architecture ready... there was no way on earth Steve Jobs would have released a Mac based on the hot and noisy Netburst Pentium4s (thought the IBM 970 wasn't far off)...
And everything Karlos has said about the x86-64/x64 is totally true. From a programming perspective these new 64bit x86 chips are a delight to code for, so much power

Just to reiterate Karlos again, the two dominant CPUs now both have 16 general purpose registers and it seems like that really is the magic number... question now is how are ARM going to figure out 64bit... because that is when they'll take the desktop (at least I'm sure Apple will go that way, and maybe M$ with Win8)
