Non-technical users are almost every single user in the world. So, if DRM prevents just those people from being able to simply email a video to a friend, then it actually is preventing most "pirating".
It prevents person-to-person sharing for non-technical users of the original content. The real question is: How hard is it for a non-technical user to find and download a pirated version from the Internet?
It's the difference between:
Hey! This track is awesome lemme email it to you.
and
Hey! This track is awesome. Google for a pirated version
of it!
Almost everyone on the internet doesn't know what a torrent is, and would stop at trying to email it to a friend. The larger share of the market IS being prevented from sharing by DRM.
They don't have to know what a torrent is to search for "How do I watch season 4 episode 2 of MY_FAVORITE_SHOW for free?" and eventually find a torrent or working video stream.
How much of the world lives in programming circles? Is it large enough for the labels to bother suing users? Regular joes/janes are more resourceful than you give them credit for.
