Remember what happened last time Apple didn't have Steve Jobs at the helm, and PowerPC processors in their Macs? Oh yeah, they went bankrupt and nearly delisted from the NASDAQ.
from my understanding, the PowerPC cpu was more powerful then an intel one for quite a long time, it may not have had the clocks but it got things done. The switch was more for compatibility reasons with software then as it relates to power. It also didn't help that around that time, price for power on intel's side was racing to the bottom where a powerpc quality chip cost far less for a pc user then a apple user.
It also doesn't hurt that apple has next to no software on its platform that if you are not a professional, you would take from one computer to the next. If you are a professional, then the software is a tax write off much like the pc is.
The only part that really has to ask a question is this.
If apple made a dumb terminal or at least as dumb as it could be without causing problems using it on its own, would they pair it with an optional base station for all the real work?
An Idea I play around with allot, what if everything that actually became processor intensive was offloaded from the main pc to a separate box? I know there are some programs that will do this, but its far from the norm but what if apple made it the norm?