The '90s MTV animated show Daria suffered from a re-release without the original music. All the MTV-era specific music was replaced with stock instrumentals, which frankly takes a lot away from the atmosphere of the show.
Is it not the case that you can buy the theatrical release, but only used, and on VHS? Or was the theatrical release never actually put on tape and sold to the public?
Han shot first. If you want to see it, you'll have to track down a very early VHS release (from 1984?) or from pirates. Every other official release has been revised for Lucas's change of heart.
Probably a copy out in my garage someplace. No idea of the version though.
But, to another point, copyright is a convenient bogeyman in these discussions--and it plays a role. But someone would also need to pay for archiving all this material and indexing it in a manner that would actually be useful.
Marion Stokes recorded tens of thousands of hours of broadcast TV from the 80s to the 90s. Without her efforts, a huge chunk of US TV history would have disappeared.