To reproduce accurate color, the capture process needs to include some method of masking to correct for unwanted color absorptions of the dyes. No positive system, to my knowledge, uses one. IDK if Technicolor did.
But, in addition to that, Pos-Pos reproduction is a "lossy" system that compresses data in the toe and shoulder during the print process. Neg-Pos processes are not and therefore survive multiple duplications without loss.
So, in regard to the OP, the color is not more accurate, but rather less accurate from a color rendition and a tone scale standpoint.
I don't understand your last point. Technicolor in its both versions (camera seperation films / camera three-layer film) is a Neg-Pos process.