I'd say it's far more reasonable to assert that the loss is due to production cost, not due to the lost sale. When you steal a bottle of wine, the grocery store hasn't lost the money you didn't spend, but they lost the money they paid to purchase the bottle of wine. Similarly, when you pirate a video game, the publisher has lost the money they paid the developers to produce it, advertisers to promote it, and factories to stamp it onto CDs (EDIT: divided up among however many copies were sold, plus 1 for your piracy, for every independent act of piracy, minus whatever income the game has generated, presumably with a minimum of 0, I THINK. Because I kind of just shat this formula out on the spur of the moment).
The problem is mostly that, in the latter case, the cost to produce the CD is negligible and all other costs have no relation to how many copies are sold, while in the latter case there's a fairly strong correlation between the number of bottles of wine sold and the cost to create them. This makes it a lot harder to deal with assigning value to the information, because the value of each copy ends up being based on how many copies there are, which is the opposite of the usual situation.
I don't have a good solution right now. But I do have a bottle of wine, so that's something.