As someone who's worked with home video departments in various capacities, I'm aware of exactly how expensive it is to store and maintain film elements, to create a new video master, etc.
Of course, with TV there's the problem of volume. It's easier for Warner Bros. or Sony to remaster an hour-long Buck Jones Western and market it to hard-core B-Western fans with a $19.98 SRP than it is to take a chance on a 30-year-old TV show with 150 50-minute episodes.
[About concerns over potentially offensive content] The mighty dollar supersedes political correctness any day. Over time labels have gotten around these issues with (for my money, overly PC disclaimers and warnings), [sic] driven by legal concerns more than anything else.