ChromeOS is one very conspicuous example. Android is also beginning to make inroads in hybrid computing use cases. Both of those are Linux kernels, though.

The more conclusive answer, though, is that writing OSes is hard. Just look at Linux - driver issues due to lack of hardware manufacturer support is practically expected. Any startup has to deal with a tremendous barrier to entry in hardware compatibility that neither Microsoft (for whose operating system practically all non-Mac hardware is made) or Apple (who actually produces the hardware that their software runs on), and experience makes it pretty clear that they aren't likely to get it right for a very long time.

Windows got the vast majority of its "buggy and crashy" reputation from crappy third-party device drivers, because as it turns out, doing compatibility for however many millions of hardware profiles is Really Freaking Hard. Apple sidestepped that issue by not even trying (ever try to build a Hackintosh?) and just limiting their target profiles to a known set, much like the console manufacturers. Anyone that wanted to challenge them would either need to be in the hardware business, or develop relationships with hardware vendors that would get them preferential treatment that Linux developers haven't been able to get for decades, and that's not going to happen without a truly obscene amount of capital.

Maybe they are but they can't get the distribution to hardware or ecosystem to develop apps for it. Most PCs are sold with the OS pre-installed. As for mobile... there is still hopes for plenty of competition. Jolla Mobile being one of the future hopes created out of the remnants of the Nokia Meego team.

I really hope Valve takes them on in some shape or form, even if it's their own flavor of Linux. Then Windows will be good for just Microsoft Office. And that's it. http://arstechnica.com/gaming/2012/07/steams-newell-windows-...