The figures in the op equate to about 109 grams / 1600 sq ft or about 68 mg / square foot of silver (109 g/1600 square ft = 0.068 g/sq ft). Since B&W film averages more than that per square foot, and color film averages much more than that (about 3X that of B&W), I have to discount the OPs original assumption and what he is trying to say via his expert.

Rare organic and heavy metal compounds (including silver) come in second.

And, labor is the highest cost in the entire equation and that is why Kodak tried for years to speed up and automate production. Which is what put them in a dilemma now.