Mobile devices, unless you get really close to the screen, have matched the retinal density for a while. Most people hold the device at about 8 inches, so 450 dpi is the value to hit.

Edit These measurements assume 20:20 vision, which is the average. Many people exceed that. So you'd need slightly higher values if you're feeling pedantic.

For rendering of text/video even an underpowered integrated gpu can handle it fine, only issue is using a bunch more ram.

For reference my very underpowered desktop AMD igpu on 3 generations old gpu architecture (2CUs of RDNA 2) only has trouble with the occasional overly heavy browser animation

You can try to configure it to be off, and while that almost works, many applications will still simply not respect the setting. This is particularly apparent (and infuriating) with apps that don't render in high-resolution mode, because their rendering then no longer has anything to do with actual subpixels.

I imagine this behavior came from ClearType having been a special case, and therefore non-native widget toolkits getting explicitly programmed to render with it on Windows, forgetting that the user should be able to turn it off!!

> MacOS went the other direction and removed subpixel rendering entirely, which is partly why low DPI external displays tend to look worse there.

Subpixel antialiasing is a compromise. Once every Mac shipped with a Retina display, there was no need to retain that compromise, because you already get high resolution so you may as well get color accuracy too.

I will note macOS still enables by default a feature called "stem darkening" (incorrectly called "font smoothing" in macOS Settings) that also looks fairly awful to my eye, and seems itself a legacy from the low-DPI days.