Dean_Demon: Hey OP thanks for the question, it's an area most gamers make assumptions on which is usually very far from the truth but i can give you my personal experience.

I am a musician and have been writing for developers for over 30 years, i do things a little differently to most other video game musicians. As i am not directly involved with a developer as a paid employee for instance i merely sell my soundtracks to them for their completed game which mostly entitles them to use it inclusively for said game and with a named publisher.

This means there is no licence or any kind as long as the publisher and developer remains the same then the soundtrack is tied to that game, but many game soundtracks today are indeed licenced which causes many headaches as the musician may revoke the developer or publisher from using it for many reasons but essentially this licence just runs out and remains the work and copyright of the original creator the musician and not the developer at all.

For me it's just a case of here's my finished work, you pay me for that work and you can use it for the condition of use but if that changes in any way then you can't use that work without informing me or just resell the product under a different name and/or developer or publisher.

If you see a soundtrack pulled from a game such as homeworld for instance then it's because of licencing reasons, many developers have resorted to using remixes or soundalike versions of the originals where the original soundtrack has been removed.

Sometimes when old games get rereleased or repackaged the original musician cannot be traced so to avoid getting into legal troubles they are simply removed. Feel free to ask if want to know anything further.