In PC gaming, Windows 10 is 38% now. It's more than Windows 7. PC gamers prefer Windows 10 because of DX12. See in Steam.
http://store.steampowered.com/hwsurvey
You mean in "Steam Gaming", Steam is not all PC gamers.
Also, Steam defaults to "Windows lastest version" in some situations (example: the stats for game purchases by platform, count as lastest windows when you buy using mobile)
Also Wine counts as Windows.
Finally, you forgot to count the 32 bits versions of each OS.
Win10 64+32 is 39.51%, Win7 64+32 is 39.54%
And for a dev standpoint, going exclusive DX12 now would still be a stupid decision, if you look in the "DX graph", you will see that only 33.52% has Windows 10 AND DX12 GPU at the same time, meaning a DX12 exclusive game would lock itself to a minority of the market.
If you would prefer "native UI", then you would hate Visual Studio as well. Visual Studio 6 (1998) was the last one which used Win32 API for the UI. Visual Studio.net (aka 2002) already had this non-standard UI controls. Even Eclipse is more "native UI" than Visual Studio, as Eclipse UI is rendered by Win32API and uses common controls. VS uses WPF and they switched to an non-native-look skin starting with Visual Studio 2013.
Btw. even Office uses non-native UI controls since the very beginning of Office programs around 1990. You can see this if you open Word 6 in Win95 (or later), the controls and even child-window theme looks like Win3.1. Office 97 had a very visible non-standard window theme with the application title in italic font (no other Win95 app looks like that). The menu bar of Office 1997 and later looks non-standard as well. Office 2007 and later draw a custom drawn ribbon area over the Win32 menu. With COM you can integrate a Word/Excel/etc document area in your sample Win32 application and you can watch how the traditional nativ menu bar is overdrawn by a ribbon area if you click inside the document area.
Last time I installed a trial version of VS, it had these weird all-caps menu bars and some kind of metro-ish, flat UI. Compared to that, Swing looked more native…
(What is it with MS changing the UI with every OS/Office release? Worse than even OS X, and barely better than the plethora of Linux look-and-feels. And yes, I did object to flat tool bar buttons back in the day, too.)