Here's the thing let's let's look at the iPad and the iPhone with a $500+ list price tag. Sorry from my perspective this is a luxury item. Let's review they have a small screen size limited memory and expensive network connectivity. What this is in a general sense is a tool;some would say a toy for the 1%'rs or from the business worldview "Decision makers".
At one point the Blackberry was slung from the hip of decision makers. Now comes the iPhone and the iPad. Problem is decision makers can't;or at least shouldn't; make decisions without "The Info" as Dr. Evil would say. The Info is provided by who at one point have been referred to a "Knowledge workers" who are they the 99%. These are the folks who crunch the numbers, prepare reports, generate the PowerPoint slides for consumption of the "decision makers". Well guess what the iXXXX can't do squat for the knowledge worker. With it's limited memory, storage, connectivity relatively tiny screen what good is it? Oh and in case anybody has forgotten Microsoft office still calls the shots and as of this writing when it comes "Office" there ain't an app for that!
Now I can see how the crowd over on CNBC can say the PC is dead because their target audience is the 1%'rs in general or "Decision makers" specifically. So let's lay this out is the PC dead for the "Decision maker", most likely. But from the perspective of the other 99% of the work force aka the "Knowledge worker" it's not dead yet.