I put two windows next to each other all the time. It's perfectly discoverable. I just drag one window on the right....
...then I drag the other window on the left.
Boom. Done. No fancy features required.
See, you're coming from a basic assumption that you will do most of your work with windows full-screened. That's not how classic macOS worked, that's not how Mac OS X worked for many years, and that's not how many of us have our workflows. That's how Windows worked back in the '90s, and the paradigm remained even though screens have gotten much, much bigger since then.
What you're demanding is that all OSes "adapt" to become a UI monoculture. So that the only way any of us can do things is the way you think is "objectively better", even though the evidence you have for that is "well, Windows does it this way, and Linux copied them, and I'm so used to it I can't imagine doing things any other way, so it must be best!"
I put two windows next to each other all the time. It's perfectly discoverable. I just drag one window on the right....
...then I drag the other window on the left.
Boom. Done. No fancy features required.
See, you're coming from a basic assumption that you will do most of your work with windows full-screened. That's not how classic macOS worked, that's not how Mac OS X worked for many years, and that's not how many of us have our workflows. That's how Windows worked back in the '90s, and the paradigm remained even though screens have gotten much, much bigger since then.
What you're demanding is that all OSes "adapt" to become a UI monoculture. So that the only way any of us can do things is the way you think is "objectively better", even though the evidence you have for that is "well, Windows does it this way, and Linux copied them, and I'm so used to it I can't imagine doing things any other way, so it must be best!"