Most folks I know who admit to pirating the wazoo out of everything do it only because it is "free" and if they couldn't pirate anymore they simply would not get the product in question.
I personally don't see a 'decline in piracy'. I think that that part of the article is a made-up bunch of hooey.
People buy stuff because they buy stuff and people pirate stuff because they pirate stuff. Do they really think the increase in sales are a result of pirates who no longer pirate?
If I couldn't listen to music for free on YouTube, will that make me willing to dedicate more of my budget toward music? I doubt it.