As a follow-up to my previous post: I think part of the problem stems from the belief that control is the most valuable aspect of copyright. As a result, (some) rightsholders will fight against any practice where they feel control is lost. In reality, as Fred laid the groundwork for in his paper, a lot of the work's value is unlocked only when control is lost. (Hint: compulsory licenses are your friend).
It seems to me this is the paradox of DRM. Rightsholders want TPM because they see it as the only way to ensure control. The problem with TPM is that, frankly, it doesn't work. It keeps the "good guys" from using works in ways that would arguably fall under fair use (or after the Grokster arguments, admittedly), but it never really protects against the "bad guys" determined to steal anyways.
Ultimately, this drives otherwise would-be customers to software like Grokster. The net result is that control, believed to be the lynchpin in the set of rights, actually has a detrimental effect on the total value of the work, including the value that the author realizes.