Downscaling the screen at "retina" resolutions works
way better than your intuitions assume. I thought it would be terrible and ugly, but I was wrong. And I'm normally super picky about things being pixel-perfect.
The way macOS does it is perfect 99 percent of the time—and it guarantees no weirdness when app developers have differing ideas about how their app should react to scaling. Apple got this one right and everyone else should just copy them.