DRM as a whole is not meant to stop piracy; no form of DRM has ever been effective in stopping piracy, nor has any of it ever been designed in a way that could be effective in stopping piracy. DRM is nothing but a trick to force customers to purchase the same product again and again; which several big DRM advocates (such as the CEO of sony BGM) have publicly declared as their ultimate goal. DRM pushers also came on records as saying that libraries are nothing but massive scale piracy by the government and should thus be shut down. It is no surprise that the library of congress (and many others) have been complaining about their inability to archive works with DRM as libraries are another of the real intended targets of DRM.
Software companies like to pretend that their product is both intellectual property which they license, as well as a physical product which they sell you at the same time. Furthermore, they pretend that somehow the two are combined so that the consumer gets the responsibilities of both and the benefit of neither while they get the benefits of both and the responsibilities of neither.
When you sell a DVD you are transferring a physical product, one that was manufactured, transported, purchased, and has to be disposed of (at taxpayer expense) when trashed. And has to be repurchased if damaged. Just like a car. This is taking the "physical object" approach.
Digital distribution does not do that. Digital distribution treats it as 100% IP that is licensed to you. You have one lifetime license to use a game/song/movie/program/etc. A license that does not need to be repurchased if your CD is scratched, degrades from age, or otherwise damaged. Therefore you are getting the benefits (you can make copies, transfer devices, and get a duplicate of the data at no cost) and drawbacks (you may not resell it) of the IP licensing method. Which is fair and reasonable; you must remember that in the license approach, you should not have an inherent right to resell an item.
If you wanted the model in which you the consumer could resell the DVD than you have to agree to a model where DVDs can not be duplicated under any circumstances, that the DVD has to be in the drive to run the game. And that if the DVD breaks then you are obligated to buy a new one at full price, even if you already purchased the game/software. This is a ridiculous notion since a DVD is worth under 10 cents, but the software on it is worth at least 50$. It isn't a car, it is a method of transferring the software, which is pure information.
Most unauthorized copying (called piracy by DRM advocates) exists to reclaim the benfits of either the license or the physical property method, but many users forget that if you reclaim both at once than you are going from protecting your rights as a customer and into the realm of thievery (which, ironically, is what the content owners do to you when they claim the rights of both and the responsibilities of neither).
I am very happy with license type digital distribution. Now in a system that no longer tries to exploit me and steal from me (which is exactly what software companies do when they pretend that their product is two different things at once) I am quite satisfied with purchasing software again. This is why services such as impulse are so much better than buying a DVD at the store.