Sorry, that really was only an example. I also didn’t say, or mean to imply, full-screen only. Every os should also let you line up windows top-to-bottom out of the box. Etc. Macos' approach of allowing one very specific combination of window arrangement, then trying to make a feature of it by calling it 'fullscreen' or 'side-by-side' (or whatever they call it) just doesn’t really cut it.
I was more like pointing out that macOS does allow for the following in some way out of the box:
> Every OS should let you line up two windows side-by-side out of the box