All Windows APIs relevant for game developers are available to UWP apps.
64 bit games, and even 64bit _only_ games are increasingly common.
Turns out for many modern AAA games 3GB of RAM isn't enough.
Worth noting: the Xbox One has used virtualization since day one for video games. Done right, gamers shouldn't even have to know that this is what's happening. https://en.wikipedia.org/wiki/Xbox_One_system_software#Syste...
Disclaimer: Microsoft employee, not working on Windows 10 (aka I have no idea how accurate this is).
The Xbox One has come up a couple times here, and I don't think the people bringing it up understand that the Xbox is the exact opposite of what PC gamers want their PC to be. It's closed down, controlled, and limited compared to a full PC. It may be more secure, but often the beneficiary of that security is not the user but the console manufacturer, game publishers, and game developers.
If this is 100% seamless virtualization that doesn't make anything noticeably slower, it might be acceptable for business users. I doubt it's going to have zero impact though...
I highly doubt it's going to fly for power-users and gamers.
As I pointed out below, this isn't even 20 year old games. Name a release in the last year - if it's not a first-party Microsoft title, chances are it's Win32.
You mentioned Diablo 1, well with polaris Diablo III would need virtualization.
Fortnight? PUBG? Overwatch? All are Win32 games.
Excited for monster hunter in Q3? That'll be virtualized in polaris.
This is going nowhere.