Kudos, and I'm glad you understand the implicit distinction I was making in reference to DRM. Hugely invasive or demanding DRM is a pain, and does a severe disservice to the customer. However, I fully advocate some basic, simple bits of copy protection simply to cover the most casual of casual piracy. Anything beyond that generally does nothing, and just pisses of the user.
I responded to the post specifically due to the example of Tribes 1's total and complete lack of anything resembling copy protection: it was maximally copyable in a way that was very rare even at the time (late 90s). It was this, and only this, degree of copy freedom that resulted in what I think are legitimate lost sales for the game.
Responding to others above, I want to be clear that I fully am aware that piracy can't be fully, or even partially, stopped. This point is blazingly obvious, so it's unfortunate to see people wasting their breath stating what we all know. That issue isn't the point. Further, as I stated in my post, I fully understand that a pirated copy does not represent a lost sale. Personally, I might ballpark it and say it might be a one in five or one in seven kind of deal (although of course that's just a wild gut guess based on jack shit).
However, my worry is that by painting the discussion in such extremes ("you can't stop piracy," "a pirated copy is not a lost sale"), we miss the inbetweensy bit that this post opened with: that there are classes of pirates, defined by the knowledge and effort they can apply to get a game. It's the first class that is the teeming masses (moreso back in the late 90s, when it was less easy for the average joe to get the goods vs. today) who, presented with a simple barrier, will wander off or, sometimes, buy the game (that one in five or one in seven deal I mentioned). If you don't even protect your product for this group of users, you end up in Tribe's boat.