Just this morning I was noodling through my start menu, as you do, and on a lark I right clicked and uninstalled Cortana. (This is on Windows 10.) Windows has never allowed me to do that before. You could disable it, you could hide it, but you could not uninstall it. The option just was not there. Some update somewhere along the line enabled an actual uninstall and I don't know which one.

Immediately I had a hunch they were planning to replace it with some new bullshit. That's the only reason Microsoft would ever let it go.