This isn't an accurate description of the situation when you buy DVD's or Blu-ray movies, though the movie studios would like you to think this way. When you purchase movies in the form of physical discs, you are buying tangible goods. You are not entering into a contract with the movie studios, and they have no say in what you do with your physical copy of the movie. You can watch it, burn it, use it for target practice or even sell the disc or rent it out.
Copyright laws (not the movie studios) do impose limitations on what you do with the content of those discs. But there is considerable legal precedence in fair use copying and shifting formats for one's own use in various types of media formats. What you cannot do is distribute the contents of the discs.
And in the US we have the prohibition on decryption, which clearly impedes fair use. This is a Catch-22 that has never been tested in the courts for an individual making copies for his own use. None of the movie studios want to press this, as they are not certain of victory in the courts. And some American judges have already indicated that they might very well rule in favor of individual copying.