"More than one-third of all new PCs sold didn't have Windows 7" quotes this excellent source:
Two probable reasons, given what I see in Best Buy and in other PC sales stores, small and large: XP, and Linux. People still demand XP when they buy a new computer, understandably not wanting the Vista or Seven chaff, nor the extremely restrictive DRM, spyware, and viral target offered by the newer versions. Then there is the rise of Linux, the belittled, embattled, and much-maligned and yet vastly superior operating system.
Linux is on 1 in 3 netbooks, and 4 out of 5 smartphones. Why don't we talk about Macs or Apple? Because all the OSX and iPhone software is based on Linux too. You can call up the native Linux interface in your Apple device by loading "X11" or "Xwindows" which is found in your OSX menu. Surprise!
Given that Macs often outsell PCs at certain times of the year, Linux is honestly resident on at least 1 in 2 computers sold worldwide and maybe more in the US, where there is a strong "No Operating System" market. I've purchased two PCs online without an "OS" present. I put Linux on them, of course.
Sidenote - Ancient Argument:
GNU/Linux, which is the origin of Linux's wingnut-reputation moniker, is widely known simply as "Linux", and there's good reason for this. Ignore the naming arguments if you do run across any, because butthurt GNU people get upset that they don't get their way, and it's a silly argument anyway. The core of any OS is the kernel. The kernel in the "Linux" OS is a Linux kernel. Thus, it makes perfect sense to call the OS "Linux." "GNU/Linux" is stupid. That's like saying we have to call Windows "Office/Windows" because the largest and most common application used in Windows is Office.
If GNU releases an OS that has a GNU kernel, I will call it the GNU OS. End of argument. Stallman really knows how to piss people off and pit like-minded people against each other.
Back to Reality:
The truth is, Open Source is no longer the future, it's the PRESENT. We're there. Windows is already dying out despite all attempts by MSFT to force everyone on Earth to use it, like it or not. The future has yet to be defined, but it's not software patents, requiring licenses to use something you've already bought, and suing your customers if they don't pay you more each year.
I'm a game developer, working on a double Masters, and my thesis is a game engine that's designed to kick WoW off the maps. It's open source, and free. But, how will you get rich, you ask? Maybe that's not my goal. I've already got money, and enough of it to be extremely happy.
There's more on Earth than the need to Sack Rome, and Pillage. Some of us like to build Universities and Libraries, which are not known for making profits, despite all attempts by University of Washington to become a for-profit buy-your-degree institution.
My gift to the world is a game that doesn't require 60.00 per disk, can be sold or transferred to a new PC, and doesn't require a monthly credit card payment to play. There are sixteen examples of competitors to WoW/ AKA Warcraft on the market now, many of which are open source. It won't be long before mine, or another persons work, surpasses Warcraft. Quake is after all an open source game, and there is no more legendary game than Quake.
Blizzard has to do a lot of work to keep you from doing anything they don't like. I don't need to worry about all that. Copy it, share it, download it, upload it, even sell it for all I care. You can't take away open source even when you profit from it. Windows is dying, and deserves to die, and I will applaud its demise.
Since I do not need to focus on licenses, middleware, and in-game payment systems, I can focus on something else: Making the game Awesome.