As much as the streaming revolution has given us instant access to more film and TV content than ever before, it's also fair to say that rights-holders absolutely did not anticipate the global pivot from physical media to non-tangible digital media "ownership."
As a result, there are thorny legal issues involved when renegotiating the re-release of a film or TV series for a new medium, especially as existing contracts often don't cover distribution on future media.
The knock-on effect of this is that a number of beloved movies and shows are left a generation or two (or three!) behind, confined to a defunct, outdated media form without any sign they might soon get the glossy HD treatment.
Leaving them to fester on older, lower-quality VHS and DVD is nothing short of sacrilege...