I am saying, again, that Post PC does not mean that PC is dead, it means that PC is not the single most important thing for software industry anymore.
Post-PC means "after-PC", as in after PCs are gone and done with. PCs and tablets co-existing (like they are) can't possibly mean "post-PC".
Consoles are and were at least as important as tablets are today, if not more, yet that didn't make a "post-PC" world. Perhaps you're just using the term wrong.
I'm not defining it any particular way, I just understand what the words mean in "post-PC" device. Perhaps you think it is some sort of mail-order PC? It has a very obvious definition, and I did in fact listen to the Steve when he was explaining this term and stooped so low as to use car analogies (like we stopped doing in the 90s because they were stupid)
I agree that one would have to be an idiot to claim that PCs are dead in 2011, but then, that's what the term "post-PC" indicates. That PCs are for all intents and purposes yesterday's news, they are the steamboats, the blimps and the telegraph of today.
Funny thing that your mother was advised by yourself (a big believer in the iDevices apparently) to buy an iPad. A shocker, just as much a shocker as it would be for you to know that I would have advised my own mother to buy an iMac. The way I see it, you just limited your mother to her current computer options, for indeed she can do the most basic things on an iPad, but if she ever wanted to do something else - such as use a computer to design weaving patterns - she's SOL.
Giving people tools that only cater to the lowest common denominator isn't what I call good advice. If they know exactly about the limitations of the device and accept it, because they can get to a PC should they need one, then fine. That's my advice. Stick to what gives the best options in case things change, because they do. But heck, it's your mother.