> it feels like Mac's UI is optimized around the assumption most users won't expand windows to fill the whole screen, but rather leave them half-sized somewhere in the middle
IMO, this has been their assumption for years, and it actually turned me off when I tried getting used to Mac circa 2006-2007. Coming from Windows at the time, I just couldn't get over a weird anxiety that my application window wasn't maximized, because it didn't look like it completely snapped into the screen corners.
Now, using 34-inch ultrawide monitors almost exclusively, I never maximize anything... it'd be unusable.
IMO, this has been their assumption for years, and it actually turned me off when I tried getting used to Mac circa 2006-2007. Coming from Windows at the time, I just couldn't get over a weird anxiety that my application window wasn't maximized, because it didn't look like it completely snapped into the screen corners.
Now, using 34-inch ultrawide monitors almost exclusively, I never maximize anything... it'd be unusable.