I think that's also wrong. I think that the primary reason media publishers use DRM is not to prevent copyright infringement. It's really to exert power over the entire ecosystem and use that power to implement rules around content distribution and use that are much more restrictive than the actual copyright law itself.

To copyright owners, there really is no difference. In many countries, notably not the USA, copyright is bound up with the broader concept of authors' rights, including the right to control whether, where, when, and how a work is exhibited. Rightsholders in the U.S. still believe in authors' rights from a moral standpoint; Jack Valenti wanted to outlaw VCRs because he was afraid of the rise of bootleg tapes, sure, but he also believed that movies were intended to be shown in theaters, and maybe only much later, licensed for television. Copyright and control over the distribution network were indistinguishable to him.