how come the iron maiden soundtrack isnt with the game ?

Last I checked, it was?

Edit: The music files are still in the game's folder, but it seems that a Windows 10 update broke something within the game's function and music will no longer play. You can get around this by following the advice below:
https://www.gog.com/forum/carmageddon_series/carmageddon_2_no_music_in_win10/post5

You mean as a goodie?

I believe the physical edition never came with the soundtrack. The songs were always played in-game.

The most probable reason is that Iron Maiden would have to agree for the soundtrack to be available separetely.

Jus to clarify: Carmageddon II's CD was/is mixed mode CD, it holds both data and music in the CD audio format, I retrieved my copy, popped the CD in and I was asked wether I wanted to listen to the music or install the game.

In the box there is this flyer:

https://freeimage.host/i/KaTslj
https://freeimage.host/i/KaTLUx

CD:
https://freeimage.host/i/KaTDOB