Developers are paid to create a game with the expectation that future sales are what will justify the expense. When a company sells its assets, including the rights to old titles, they're setting a precedent that makes it more likely that others will take a risk by funding game development.
Undermining the industry by not purchasing a license to a game you're playing at any point is problematic both morally and legally. It all channels back into business decisions about green lighting future titles.
Your logic is sound but you don't specify a magnitude. For every one million pirated copies of Panzer Dragoon Saga, how many Condemned 3s are we not getting because of the risk calculation? What's the regression coefficient?
Because it seems to me like the proposed harm is a rounding error. I mean, coups in African nations could disrupt supplies of minerals used in hardware production, so they're a factor in the greenlight regression model, right? If we can't get our Cobalt Trioxide Dilithium or whatever, hardware supplies dry up. And if China tests an EMP bomb, online-only games won't be playable, right? Or, like, Propeller Arena got cancelled because 9/11 happened. Do you think the greenlight process had a penalty built in "well, there's an xyz% chance that a world-changing event will occur resulting in us not being able to make the game"? What do you think XYZ% was? But is it worth discussing those factors? Probably not. In statistics, they're in the μ, right, not the explanatory variables of the model?
Hell, here's a good way to have this conversation. You're Warner Bros. Monolith pitches you on a game called Lord of the Rings Chess, exclusive to Ouya. Write me a fake greenlight report that touches on the kind of concerns you think publishers have. How did competition sell? What's the hardware install base? What kind of Metacritic can we expect? What's our ad spend? Where in the report do you think they quantify the impact of piracy of this game in 2035? Note I'm not talking about how they incorporate in piracy to the sales projections, I'm wondering what section of the report discusses the abstract value of the assets decades from now.
I can buy that piracy impacts greenlighting decisions in a somewhat material way. I think if you expect to sell 1.5 million copies and sell 1.0 million copies because of piracy, that's scary, and is part of your calculations. But in your story, you sell the 1.5 million copies and then 15 years later when everyone who worked on the game from the publishing side is dead, retired, or fired, and we're playing games on Holo-Sexbook while in cryo-sleep on the way to Mars Colony 3... the resale value of the asset is devalued in an abstract way because people out there are copying shit your company has long since forgotten about? I'm not buying that for a second.
Especially since we're in a counterfactual world anyway. OP is willing to buy the game and will if it's resold. It's true that every pirate says they "would" buy the game and most of them are lying. But in this counterfactual world, the OP is being honest, so I'm not even sure you can make the argument there's some abstract lost-sale mechanism at all.
Finally, it's 2015. Anything made now (except licensed goods, but those are also exempt from your argument about resale value of the asset) can be sold digitally forever with no risk or maintenance cost to the publisher. So if the items do still have some value, why wouldn't they continue to be sold forever? So then... if this kind of "abandonware" (not a legal term) piracy is factoring into greenlight decisions... wouldn't it no longer be factoring in, and thus any game impacted by it has already been greenlit or not?