There's a good section at Wikipedia about the difficulties in determining the penetration level of GNU/Linux on the desktop: en.wikipedia.org/wiki/Linux_adoption#DESKTOP
Estimates vary from 1% to 10%. A couple of quotes:
In 2009 Steve Ballmer indicated that Linux had a greater desktop market share than Mac, stating that in recent years Linux had "certainly increased its share somewhat".
Carla Schroeder : There is something else that is even more persuasive, and that is how Microsoft behaves. If Linux is so insignificant, why do they pay so much attention to it?
Like many people who write a lot of software, I far prefer the GNU/Linux environment to Windows. Unix was designed by programmers to provide a productive environment for programmers, so there are lots of useful tools like grep, diff, sed, make, and od/hd built in. You can also get most of these capabilities on Cygwin, which mimics a GNU/Linux environment on a Windows machine. Now should you count Cygwin as GNU/Linux or Windows?
As far as consumers are concerned, many used Windows PCs because it was the best choice for them at the time. Now many use smart phones and tablets, very few of them running Windows. That doesn't affect the "desktop" numbers, except that they would have been using desktops before and now are using iOS or Android/Linux so this reduces Windows if you add them to the mix.
Many companies are looking into using Chromebooks or similar machines as thin clients, with all the real computing done by cloud computing.
Microsoft clearly sees Linux, especially in the form of Android and Chromebook, as a real threat or they wouldn't be cutting Surface prices so drastically in an effort to compete. If Window's position as "king" was solid, Microsoft could charge what they wanted to for these machines and Windows laptops wouldn't be so cheap.
We still haven't had the "year of Linux on the desktop", and I doubt there will ever be a sudden shift. Linux has always been slow and steady. Earlier this year Linus Torvalds said half-jokingly "I still want the desktop". I think he'll get it, eventually.
It is interesting to reflect upon the changes of the past 30 years since the iconic 1984 advertising campaign for the Apple Computer. Who would have ever guessed that today a powerful laptop home computer could be purchased for less than a popular telephone?
Microsoft has to expand and compete, in order to survive; you have to 'have a go' at a new product segment, even if it's just to see whether things will succeed or not.
Tablet market (with Surface) was not really "worth" Microsoft's efforts either. If you think about it, they could've just OEM'd RT and Pro to the usual crop of hardware partners, but they decided to get in their themselves (and now through Nokia) as well.
This kind of 'exercise' is good for Microsoft; it keeps them fresh, in competition with the 'web' crop of companies, like Google and ups their marketshare, making them more investable.
IBM does the exact same thing. It's all about marketing and shareholders but being successul in a new segment won't hurt either!
Because no one wants Linux on a desktop/notebook computer. Ubuntu and Mint have been trying for years and every year is touted as the "year of Linux on desktop" but it never materialises.
Linux seems to be confined to the enthusiasts, hobbyists and hackers; mainstream business/consumers don't want to know. Why? It's too complex and fragmented.
Regardless of how you might look at Windows (in all its iterations) it's still king and seems, it will continue to be. Hardware always needs an OS and Windows is leading the business market, despite having lost a great deal of its lead in the consumer market to tablets and smartphones (not Linux or Mac though!)
Also, because for Linux to get on a desktop or a notebook, it has to uninstall Windows first; no major PC vendor sells Linux pre-installed on their machines very much, because it's not popular.
And to be fair to Microsoft, they're exploring new territories and seeing how they can (a) keep up with the new crop of 'web' companies and (b) finding new markets for their Windows vision.
There's a big opportunity in this market for a low-end laptop with neither Apple, Google or Microsoft on it. Mine has LinuxMint, but I had to pay the Microsoft tax first. Yes, I do my taxes on it, plus edit video and a few other things, usually off-line.
Yes you can buy a traditional laptop and get the traditional short laptop battery life, a loud fan and the cheap slow HDD... Or you can get a Chromebook with better battery life - there are now versions that last 13 hours!
As for numbers, see eg. http://www.gartner.com/newsroom/id/2819917 As you can see ARM based Chromebooks are by far the most popular. The wave of 64-bit ARMs coming soon will provide an even better alternative to x86 based laptops. Chromebook growth rate for 2014 is estimated at 79%.
I'd love to see numbers on Chromebooks. It got huge hype when announced 3-4 years ago but didn't get much market traction, then went quiet for awhile and now seems to be having a minor comeback. Samsung opoints to it as a design win for Exynos and Nvidia as a design win for Tegra.
It does seem like the future of cloud centric computing, getting rid of the "Windows tax" of a ~$50 OS royalty. But it still seems like a far future when you can buy a machine with a half terabyte disk for another ~$100.
"would they need developers to build more applications for the product?" I expect that they are looking for free, advertising supported apps that Google users now tolerate. The capability of such apps are typically much less. App store counts are part of it.
My wife is replaceing an old Mac and today's Fry's ad features a $225 15.6" laptop with a 320Gb drive and 2Gb dram. Of coures, it's Windows 8.1. That's less than I paid for my nexus tablet.
I'm happy with my windows 8.1 but I must admit, I usually use it in "classic shell" mode.
I'm worried about the 2core celeron processer though. But the price is right.