Windows 7 still owns well over 50% of the operating system market share as of May 2015 thus making it far and away the weapon of choice for PC users across the globe. This is in part thanks to Microsoft's lack of a clear update mechanism and additionally because of the pig's ear that it made of things when Windows 8 was released.
Indeed the newest version (Windows 8.1) owns just 12.88% – which is only enough for it to secure third place behind Windows 7 and XP (the latter is on 14.6%). Microsoft will remedy this with a brand spanking new update process when Windows 10 is released, but whether or not it comes close to the Apple Mac App Store's slick and easy OS X update process remains to be seen.
The day when Windows 8.1 garners a majority market share of the Microsoft ecosystem has already failed to materialise and its days are numbered thanks to the imminent arrival of Windows 10, which will be a free upgrade for all Windows 7, 8 and 8.1 users for 12 months.