That's a totally different, much simpler question. A stolen DVD is very clearly a reduction in the number of DVDs the seller can possibly sell.
It could be that this stolen DVD allows N people to discover its content and buy the DVD. The seller wins from this stealing even for a small N. N could be bigger than when downloading the movie instead, because the DVD can be seen in a shelf for example.
Is it fundamentally different? (it's a genuine question, I have not studied anything on the matter).
The only difference I see is that almost nothing = zero when downloading the DVD's content instead of stealing the physical object.
edit: I actually see a difference, there's no guarantee that a stolen DVD does produce any sale, and so there is a loss even if it is small, but I think the question is still not simple to answer.
That's true, although I was thinking more about retailers who presumably pay much more than the marginal cost (though still much less than the retail price). It's also probably true that copyright laws are responsible for the vast majority of the commercial value of physical copies of digital media. Perhaps an easier way to see the fundamental difference is that when you're downloading a copy of a movie from BitTorrent, all the parties actively involved are willing participants.
> It could be that this stolen DVD allows N people to discover its content and buy the DVD.
This is also a real possibility, and is a strong argument for copyright holders to rethink their business models (and, in my view, for societies to rethink copyright laws). But I don't think it's a strong argument for treating the theft of a physical DVD and someone torrenting a movie as being remotely comparable.
Edit: I'm making it clear I absolutely despise this argument of course :D Being able to buy/sell used physical media is my favorite reason to buy physical and never buy digital.
I could play Mp3s on a 20 year old computer. That 20 year old computer won't work with apple music lol.
Hell, I can play DVDs that I bought 6 months ago on my 17 year old PowerBook G4!
Even if you used the wholesale price for theft, it wouldn't make a big difference. There's a real burden there that's very close to a lost sale even if it's not actually a lost sale.
With piracy none of those costs exist, and any costs that do exist are paid for by the pirate.
But that's not true; you would have to assume that the number of DVDs the vendor orders is independent of the number of DVDs the vendor loses to all forces including both sales and theft. That assumption is obviously false. If you run a store, you're not limited to ordering a single shipment of whatever DVD; if it sells well, you can order additional shipments.