Can you replicate a drug all by yourself at an essentially zero cost?

Making another 100mg of a medicine may cost essentially zero on a pharmaceutical plant, but you can sell the access to the plant.

Copying data is not just easy, but you have already bought the "factory equipment" needed for it, that is, a computer. Thus the drive to dumb down consumer computers (DRM) or move the essential things from users' possession so that they could not easily copy them (SaaS).