I saw many dvd movies on blu-ray disc
Here a link:
you will see it on the Right side of the webpage

Now Back to the Question...
I know BLU-RAY disc have a Memory of Almost 50 GB
(Thats why its called The Next Generation Disc)
Then they Burn Just Only One Movie???
One Movie (Best Quality Video) is only about 2-3 GB
I think Its Just a Tiny little space on disc..
I think they only waste that disc..

Adittional Question:
What CD's Made of?
Why is it so cheap?