Comment by perching_aix

They really don't. Though if Microsoft wanted to, they could solve that too. For example, the OS control panel used to be extendable. Technically still is, just not the new one (and of course both remain). Then you could have this UI or something very similar to it right in there.

Several integration points like this have been removed, supposedly because third party software was just too bad in how they used them, causing issues. Or at least so goes Microsoft's perspective. Personally, I find that very believable! If by integration points the only thing one can imagine is calling into random third party code on the regular that the user has installed, bang spank in the middle of critical user flows, on the same thread and in the same process as itself, that's exactly the kind of grief I'd expect to occur...

If only there was a way to provide a way to craft e.g. custom flyout menus for the taskbar or custom pages in the Settings app, without invoking arbitrary third party code and possibly causing crashes and hangs in system apps and menus... or just not letting crashes and hangs affect the application (e.g. Windows Explorer) calling them in the first place.