Two sides to the coin - and for the 1000th time in 100 years... PCs are not dead
There are two major aspects at play here with the lower sales:
1) has already been touched on, that essentially a 2-3 year old machine is plenty good enough for the large majority of users to make documents, browse the web, watch HD video and maybe play occasional games.
2) The Global Economy (especially the US and Europe) is very depressed right now... when its not feeling so sad in few years I expect PC sales to pick up again.
Here is why:
For one, for browsing and documents, even a 10 year old computer could do all that was needed for 90% of the people out there. But then, as we will again in the future, we buy things we don't need. We buy them to have bragging rights, we buy them for future proofing and caution, we buy them to expand our computing capability. And when money was more expendable, we bought them more frequently than we needed to.
There is a lot more you can do with a real PC these days, and the Operating systems, and set up of services is easier that it ever was.
- Sure you can play Minecraft or similar games on a tablet or old PC, but on a new PC I can play and host my server
- On a PC I can rip by Blue-ray and DVD disks, and re-format the movies to fit smaller sized screens like my smartphone or tablet... a fast computer will do such actions with few clicks and only takes a few minutes. Its faster than say even downloading an illegal already formatted for Smartphone version of the movie from bit-torrent or similar file share.
- I can stream music and videos from my main new PC to the older weaker PC's, smart phones and tables in the house (or over the net even) A Modern PC can host 6-12TB of data easily, which will usually hold all your pictures, and your entire movie and music collections of the average person
-Security and Multitasking.... unlike the older PC my new PC can do all of the things listed above, but it can also run multiple Security programs AT THE SAME TIME.
Anti-virus, Firewall, Anti-spyware (3 versions), Anti-Trojan (two versions) and other programs like Windows defender, Linux Firewallls and root kit detectors etc.
Smartphones and tablets are neat, but the large majority of them don't have on access virus detection, firewalls or other typical security features that PC's do. Old PC's can run these security programs too, but only with a serious performance hit.
Gaming: This one for me is a no-brainer....I will be buying a new $1500 gaming machine at least every 2-3 years for the long forseeable future (and that's a bit of a compromise budge gaming rig, they can run $3,000-4,000) PC gaming always has been, and will continue to be a world apart from console gaming. There is usually a very brief period when a console first come out that it is maybe comparable... but still lacking, within 6 months they aren't even close. PS3 and Xbox are over 3 years old, and even 3 years ago a $1500 machine would beat the pants off of them. Just 2 years ago progress in the PC marketplace had put these kiddie boxes to shame. Games like Skyrim, COD, are getting photo-realistic and attracting larger audiences. As kids grow up from consoles, I expect a lot of them (the serious gamer ones anyways) will naturally progress to PC gaming and all the great worlds it opens up.
PC's aren't; going away any time soon, though manufacturer should be getting smart about how to keep their numbers up, as tablets, old and budget PCs and smart phones will continue to eat away at their market share.
If I were running a PC business today, I would be looking to load a dual/boot Windows 7 and Linux (Ubuntu or other) as a default image... and load up the Ubuntu side with plenty of tutorials and free software.