Remember that there were also big campaigns against tape recorders and VCR. They even managed to get VCR vendors to implement a feature that prevents users from skipping ads. So it’s not like it’s simply legal, the media corps were just not as successful in their lobbying as they are today.
Sure, but the thing is: only a single person needs to break it temporarily in some way and this person can then leak the DRM free copy for everyone to consume.
That’s why DRM is such bullshit. It only ever punishes legitimate users. All others are unaffected.