The fact that there are downloaders proves that there is demand for the items in question. I find it difficult to imagine a price elasticity scenario whereby not a single person among those downloaders would have paid a single cent to the studios in order to fulfill the demand had the option to freely, illegally download not been present.
Do you honestly think that DVD sales are not even slightly affected by pirating?
I think DVD sales are affected by the fact that people watch films on computes and not TVs, to attribute that to piracy is just wrong.
The fact that people download something proves only that there is a demand at cost 0, how this translates into a demand for a physical item at a cost >0 is hard to tell and sure not linear.
Just because they didn't make more profit doesn't mean they lost profit due to downloading.