An Ongoing Trend:Unreleased Complete Film Scores online!!

Here's something that I've noticed recently. Online in some occasions I've noticed that there are Websites that Have the complete (or Expanded) scores of many movies. (Many that I like)

Here's What I've Found Online:
The Mummy (apparently this is from one of the DVD releases)
Star Trek 2: TWOK
Star Trek: FC Info Here
Born on the Fourth of July
The Shadow
Harry Potter and the Sorceror's Stone
Jurassic Park
First Knight

Many of these are Here

Why can't they be Released?? (at Least in Limited Edition format, I know wishful thinking)
And what Score would you like to see released in Complete Format (including Alternate themes)

How hard are they to find on File sharing Networks?