You have expertly summarized the first and last lines of my original post about Color NTSC. Interlacing is effectively dithered color super-resolution at low frame rate with blur from fast motion line tearing at the interlace rate.

   Your cones are surprisingly low bandwidth (why old color TVs even worked at 
   30Hz), while your rods provide danger/flicker cues outside the fovea.
   
   Uncorrelated subpixel scale dithering works just fine at 30Hz.