It's mostly due to legacy rights issues, such as licenses for songs on the shows, films etc. Royalty agreements with the screenwriters, etc.
They can all be worked out, but it's expensive, and takes time.
The BBC faces the a similar problem with putting its archive on iplayer. It may be public funded, but they didn't buy unlimited streaming rights from their writers, or from the music publishers.
Biting the hand that feeds IT
