To clarify the reason why - the original release of 4K77 (v1.0) has its color white-balanced but otherwise more or less unchanged (or something very close to that), because at the last minute nobody could agree on the different color grading attempts that were being put forward.
When work began on the DNR version, it was discovered that applying DNR to the image revealed more dirt, dust, and scratches that were largely hidden (or made mostly unnoticeable) by the grain. So they went back to the pre-color-corrected master files, DNR’d them, then did a whole second cleanup pass to the film. While Williarob was doing this, he decided to tackle the color on his own this time, on a more or less shot-by-shot basis.
This means that the DNR version of 4K77 has an entirely different base color grading than the no-DNR version, so you can’t just take Sanjuro’s color correction of the no-DNR version and apply it to the DNR version, you’ll get an entirely different (and very wrong) look since it would be a grade on top of a different grade.
The new v2.0 is being done in a similar way to 4K83, so that there will be a base version with a standard color correction that will be used to make the DNR and no-DNR, which means from v2.0 forward, color grades can be applied to both DNR 2.0 and no-DNR 2.0 without any of the issues that would come with trying to apply a new color grade to DNR 1.0.
Hope that helps explain things a bit!