"How Windows 10X runs UWP and Win32 apps"
https://www.youtube.com/watch?v=ztrmrIlgbIc&list=PLWZJrkeLOr...
MSIX
https://docs.microsoft.com/en-us/windows/msix/overview
> Apps that are packaged using MSIX run in a lightweight app container.
Yes, Win32 can still choose between both models in current versions, depending on Windows 10X reception, I bet it might eventually change.
Sandboxing resistant developers are always free to keep their Windows XP or 7 copy, I guess.