Why isn't title "X" available on DVD or Blu-ray?
Now that DVD has effectively killed VHS and Blu-ray is starting make DVD a second-class format, everyone wonders about those films never released on DVD or when an older film will be available on Blu-ray. There really is no easy answer to this question. Each studio evaluates demand for an older catalog film and must justify the costs of releasing a particular film on any physical format.
Many studios are experimenting with Manufacture on Demand (MOD) options that will allow them to release older films on DVD despite having relatively small demand. Also, with the proliferation of digital download options, it's possible that studios may make some older films available in a digital format in the future.