It became untenable well before that for certain people. It's all stuff that can be changed or disabled but the Start Menu in Windows 10 with the tiles, and its default search on Bing was infuriating. I do tech support and some clients just don't bother to deactivate it. There is also the whole thing about Microsoft removing parts of the old Control Panel and its utilities.

But another aspect of why they may also be losing market is how bad they have been with other architectures, like ARM. Windows for ARM seems to be lacking a lot. Even though they have been slowly getting better with emulation, they are still very much behind macOS and Linux. And I'm just a level 1 tech, but it seems like ARM devices and other low power architectures will slowly replace the old home desktops. They may have made a big mistake there.

But they still hold the corporate world and governments by the balls so, it's gonna be interesting to see.