shmerl: Note - "exclusive games" and "Microsoft technologies". So, expect everyone to be excluded, unless they are using MS stores and MS platforms and expect more push for MS only lock-in like UWP and DirectX, instead of collaboration on cross platform technologies. And the goal is not to reach more gamers, but to turn gamers into "loyal Xbox fans"...
^ This. Anyone arguing over store-fronts needs to be reminded - This is the same Microsoft that cancelled multi-million title selling Ensemble Studios (Age of Empires, etc) because the style of play couldn't be dumbed down enough to fit XBox controllers. The same studio whose Quantum Break defaults ran at upscaled 720p on the PC for "platform parity" with the XBox... Expect future titles to not only not be here on GOG, they probably won't even be on Steam either. See Age of Empires Definitive Edition for an example right now.
"Microsoft Technologies" is the agenda reveal here. It's all about pushing XBox sales, forcing further W10 adoption amongst older gamers and trying to reassert DX12 as the "dominant" future gaming API after cross-platform (and better optimised) Vulkan has been stealing its thunder and enabling games to be easier ported to Linux / PS4. The ultimate worst case end goal would be abusing their control over W10 and forcing UWP / DX12 to become the "Win32" / DX11 replacement by gradually deprecating older DX. Eg, first "test the waters" by removing DirectPlay support from W10, then gradually DX7-9, then DX10, then finally DX11) and end up requiring games devs to use only DX12 / UWP to finally depracate "Legacy" Win32/64 apps (also to force people onto newer MS Office versions). Whether they'd be legally allowed to get away with it I don't know, but there's no question MS haven't thought long and hard about the fact W10 is one potential giant kill-switch for all older applications / games waiting to happen, not in the immediate future but certainly perhaps in 5-10 years time.