> The flat "Metro" UI style was initially modeled and developed on Windows Phone 7,

Originally it was for Zune, which inspired Windows Phone 7, and then it was horrifically mangled for Windows 8.

WP7 Metro had a ton of affordances to make the phone easy to use, things like scrollable pages of content should always show a peek of content that is below the current view, so users know there is more content down below.

Common sense stuff that has been forgotten. :(

... and then most if not all the mobile/tablet part was abandoned, at the time the concept was dubbed "continuum":

https://www.microsoft.com/en-us/windows/continuum

https://docs.microsoft.com/en-us/windows-hardware/design/dev...

https://en.wikipedia.org/wiki/Windows_10_Mobile

and it had its merits (from a phone-centric view) but the (crappy) UI remained even when there was not any more need for it (and a Windows 2000/Windows 7 like one would be much more suitable to laptos/desktops or anyway for no-touch devices).