I seem to recall that was sort of the plan starting with Windows 8.

On the inside the "metro" core runtime (can't remember the name) was not depending on the historical win32 parts, and on the GUI the win32-dependent desktop appeared as a tile i.e conceptually an "app" on the start screen. Like a nested VM, but at the library level. I could have readily imagined multiple desktop tiles being there, one per legacy Windows version, to maintain some sort of perfect backwards compatibility without emulation, Wine style?

You could see a path forward where the start screen OS was not a layer atop the desktop, but the main thing with the legacy desktop boxed inside, possibly in the future only installed when a legacy app required it, and pruneable anytime. It made me think of the Win95+ transition ultimately leading to the MSDOS dependency being turned around and dropped.

Of course mistakes were made, and people cried foul about losing the desktop, so back to the desktop it went, with its legacy cruft.

Maybe indeed it can still move forward that way by using a more "Fusion" like approach where foreign legacy Windows appear on the desktop (like WSL2+GUI).

They've even sort of done this before on the Xbox One. That thing runs many OSes at once!

That's actually what they were doing[1] in Windows 10X, now cancelled.

I guess the future of Windows continues to be the Win32 API.

[1] https://www.youtube.com/watch?v=ztrmrIlgbIc

Yes, some sort of containerization could solve all this. Drawback is size on disk, however with today’s disks like m2 I don’t think it should be a major problem.

WSL1 was not a VM