Comment by estebank
7 hours ago
They tried that during the Chicago development and discarded the idea due to multiple problems with how humans work.
Two different UIs meant that you had to learn them separately, you didn't have a slow ramp from one to the other, one familiar with one could get stuck on the other with no knowledge of how to get back, divided efforts between the two, etc.
Not quite what you are asking for, but closer to Win95 shipping with progman.exe which could allow someone to cosplay Win3.11 while running Win95.
And yet they seem to have lost all that knowledge from Win8 onwards. WinForms, WPF, UWP, WinUI, MAUI... All of these with their own metaphores, design language, and they all feel half-baked, full of bugs.