And physical media's never stolen, right?
The data to validate this is scarce, but I'd wager that most rips come from stolen physical media. I don't think there's too many people out there going "I just paid $20 of my hard-earned money for this Blu-ray, so now I'm going to give it away to strangers for free". The whole "paying for something" thing is kinda antithetical to piracy in the first place. But again, there's no real way to quantify this.