It's not about desktops either. If people are using notebooks, their using PCs. So even if people have really old desktops in their homes that aren't being used, because they have a more recent laptop, THEY'RE STILL USING PCs.
Even these convertibles will count as PCs, or tablet PCs, and unless they use Atoms they'll continue to count as full PCs or tablet PCs in terms of Intel's processor sales at least.
And then people keep saying that Mac OS X market share is on the rise. ALL Intel Macs are PCs FFS!
Consider this: My college has made laptops from this semester onward. Their recommended spec is a Core i5, 6GB of RAM, a 2GB GPU and a 750GB HDD.
It's excessive for the intended purpose (online tests and assignments), but the point is, it's not doable on a tablet or phone.
Tomorrow, I'm going to pick up an old Intel MacBook from a family friend who's had it lying around unused (BECAUSE HE BOUGHT A NEW ONE), i'll throw in an SSD, Install mountain lion, add more RAM, and i'll be set till graduation.
If i need heavy computing (i'm in engineering college), or for playing games and stuff, i have my Windows 7 based desktop (WHICH I'LL UPGRADE TO HASWELL THIS YEAR).
We're also moving to a new home, where i may set up a media file server...
So what post PC era? Stop talking about it untill it comes. Or until the ipad plays Crysis.