Just FYI, the major advantage in neg-pos systems is QUALITY. Pos-pos duplication causes inevitable deterioration of image quality due to the printing of toe to toe and shoulder to shoulder. Tsk! Tsk! Don't eliminate the most important factor and build on a weak link.
In addition, at EK efforts were made to speed up and spectrally sensitize many of the old processes, and they failed. It turns out that the grains grown in gelatin are the key to today's HS photographic films.
This is a nice premise based on totally incorrect starting assumptions that just, for me, terminate the discussion at the outset.