That could change. Microsoft has shown time and again that they don't care about PC gaming. To Microsoft, DirectX is a tool to persuade customers to upgrade Windows & hardware when its rarely needed these days. Thanks to the newest consoles, PC gaming will be mostly stuck at 1080p on a mid range gaming PC for the next 5 years. Sure they'll support higher resolutions but with TV screen FOVs & UIs.
Steam as DRM is as effective on Linux as it is on Windows and most games companies have realized that 'tied to an online account' is about as much DRM as most people will tolerate.
With the platforms being so similar it should be easier to port games these days. If they're smart they'll write as much code as possible to be portable to between XB1 & PS4. Porting code to Linux should be much easier now that the PS4 is an x64 CPU running a FreeBSD derived OS. It wouldn't surprise me if games start to be released on PS4 & Linux but not on Windows.
I'd love AMD to release a Mantle PS4 API for Linux.