Speaking as someone that bought into it, WinRT was kind of the .NET idea before they went with a Java clone (Ext-VOS), they didn't fail only on features, they failed on how it was managed.
From the forced rewrites across Windows 8, 8.1 and 10, as the platform was maturing, the deprecation of C++/CX, replaced by less capable C++/WinRT (now in maintainance, while they are having fun in Rust/WinRT), deprecation of .NET Native without parity in Native AOT, no designer, and plenty of other broken stuff.
It was for this that WinDev kind of sabotaged Longhorn efforts, thanks very much.
Meanwhile Google shows what happens when everyone pushes into the same direction, even if it takes some growing pains (with lots of cash) to get there.
