It’s effectively supersampling. The resulting image looks excellent.
Most people (and companies) aren't willing to spend $1600 on Apple's 5K monitor, so they get a good 27" UHD monitor instead, and they soon realize macOS either gives you pixel perfect rendering at a 2x scale factor which corresponds to a ridiculously small 1920x1080 viewport, or a blurry 2560x1440 equivalent.
Are you sure you aren’t confusing Window’s terrible font rendering with sharpness?