Why do some blu ray tv shows come with special features and some do not?

[Movie shy]

Was wondering why some tv show like the Twilight Zone are packed with special features and some TV shows have no special features? For instance I was thinking of getting the complete series of Quantum Leap on blu ray but was told there are no special features. Yet you have shows like The original Star Trek series that has tons of special features (don't have that set but heard about the special features). As some of you may know from my posts I love special features and that is why I have bought certain movies over others that do not have any special features. For Quantum Leap they could have some episode commentaries thrown in and an interview with Scott Bakula but they don't. Since that show is being released by Mill Creek I shouldn't have been surprised that no special features are included.