Clive;

My answer was to this statement "As we know from history the neg/pos process eventually came to dominate for obvious reasons of replication" which should have read "As we know from history the neg/pos process eventually came to dominate for obvious reasons of quality when replicated"!

What would we not have?

Color, speeds much over ISO 1 or 2, stable images (Daguerreotypes degrade much more than Silver gelatin - I've seen enough at GEH to convince me of that!), high quality duplication (see my alteration of your quote) and probably motion picture.

That is what we would probably NOT have today.

PE