Gartner says that something else explains the sales decline: "Consumers are less interested in spending on PCs as there are other technology product and services, such as the latest smartphones and media tablets, that they are purchasing." Given the raging success of the iPad and both iOS and Android smartphones, that's an easy explanation.
Gartner also says the gravitating to tablets and other newfangled devices is more pronounced in developed countries. That makes sense -- almost everyone in such countries already has a PC, so nearly all sales are replacement sales. And why replace a PC that works OK, especially when there's something cooler to spend your money on?
But both Gartner and IDC point out a troubling fact: That gravitating is also happening in less-developed countries, where PCs are less established. That suggests many Asians, Africans, and others may skip the PC entirely. That has dire consequences for PC makers, with or without Windows 8. And although Mac sales are doing relatively well in the United States, Mac sales in most other countries are minor; the American infatuation with MacBook Airs may not translate overseas, even as the iPad does well. Apple is doing its best to attract buyers overseas, as the strong focus on Chinese native services in OS X Mountain Lion shows. We'll see if Apple's Macs can buck the general post-PC trend.
Windows 8 is not likely to jump-start PC sales
It's possible that Windows 8-based tablets will become as popular as the iPad; Microsoft's Surface tablet certainly looks compelling, in both Windows RT (ARM) and Windows 8 Pro (Intel) guises. If you don't use the Windows 7 desktop portion, or use it very little, Windows 8 on a tablet is compelling. A good selection of tablet-optimized software could give Windows 8 tablets -- and particularly Windows RT tablets -- a big boost.
But not Windows 8 desktop PCs, laptops, or hybrid devices. In my experience, even with touch-friendly hardware, the old-fashioned desktop in Windows 8 is very difficult to use -- legacy apps, even Windows apps, weren't designed for touch, and the result is painful. I suspect most users will avoid Intel-based Windows tablets as a result. As far as Windows 8 desktop PCs, it's not clear why anyone would want one. The Windows 7 part is, well, Windows 7, albeit with a few new bells and whistles. No matter how you look at it, the Metro side of Windows 8 is awkward on a desktop computer, even if you have a touchscreen.
I simply don't know too many people who are currently waiting with bated breath so they can buy a new PC with Windows 8 on it. I did know people who were genuinely excited about buying new computers with Windows XP and Windows 7 (primarily to ditch Vista), and of course to buy the popular but pricey Retina MacBook. But Windows 8? No way.
Windows 8 may well be the new Vista or Windows Phone 7 -- an albatross of a product, destined to serve primarily as an embarrassing stepping stone to new products. Perhaps Windows 9 or 10 will do better, but for now what we've got is Windows 8, and it doesn't bode well.
I may be wrong, but I believe Q3 2012 and beyond are going to be one very tough ride for PC manufacturers.
This story, "What the PC sales slump really means -- and why it will get worse," was originally published at InfoWorld.com. Get the first word on what the important tech news really means with the InfoWorld Tech Watch blog. For the latest developments in business technology news, follow InfoWorld.com on Twitter.