I think it's more intended to (a) prevent casual piracy, and (b) to provide a legal stick for the cases where people do things like break-and-resell.

Don't get me wrong; I have no illusions about the industry. If they could figure out a way to reasonably eliminate all "ownership" and charge you per read; or, better yet, charge you a recurring fee whether you read or not (hello, subscription services), they would. If there are circles of hell, most of these people would find themselves in the fourth.

However, I think it's only worth the effort of prosecuting for gross violations, and probably few people in the companies care about folks de-DRMing their books, as long as they aren't sharing them. It's not hard to break the DRM, but it does require more knowledge and effort than, say, my mom is going to bother with.

The DMCA is still a stupid law, and should be repealed. This age of "you don't own something you buy; you only rent it" is the ultimate stage of capitalism where it becomes almost impossible to defend.