Who a thunk it. The labels have things so tight in the copyright department that the studios cannot release old TV shows to DVD 'cause the labels want too much money for the rights to the musical score. Apparently the studios neglected to sign air tight agreements with the musicians back when the shows were produced. Some are quite old, say The Fugitive from the '60s, back when VHS and DVD rights hadn't been imagined.
It's so bad that some of the old shows are released with a new score, just to sidestep the copyright tangle on the original score. Which is incredible, redoing the score on a 40 year old TV show has got to be expensive. You would think in a real world it would be cheaper to buy off the labels than redo the score on a TV show.
The labels probably use the same lawyers they sic on file sharers to gouge the studios.
And the studios really really need to get better lawyers and make sure they own ALL the rights to the scores of their productions.