I wonder how much of this is due to Windows font rendering currently being so focused on ClearType. At 4K and 27", you don't need subpixel rendering anymore, because your regular pixels are small enough, but you do still need grayscale antialiasing. As far as I can tell, Windows no longer supports grayscale font smoothing — it's subpixel or nothing, and "nothing" still looks bad except for bitmap fonts being displayed at exactly the size they were designed for.