@alaannn: Product placement is not the game itself,its commercial deals made with several other companies in the game itself.For example: In Splinter Cell Sam Fisher uses a certain Smartphone,in Mega Man Legends there was a Deal with a Lemonade Company only for the japanese Version,Sports and Racing Games are full of it.If the deals run out,they are not allowed to re-release the game without changing all the textures.If just ohne small thing whould not be removed they whould be sued their butt off and have to remove their game from the stores.
https://www.youtube.com/watch?v=oMS23XGrQzM

@alaannn: But the effort behind it is higher then the expected earnings,And that is the reason why some games didn´t make it.It is too expensive and complicated.And those deals contain more then one Song in a game.Some Devs/Pubs even stated it in public.
And we are still just talking about the music - its just a small part of it.There is still product placement (which was in Megaman Legends a big problem),Engine-deals and other issues that can prevent them.

@alaannn: If it is a normal music file it may be so - but its not like they put simple mp3s in the data packs and you can just erase them and you´re done.In most cases its very far from it.

@alaannn: Then you should look at the data structure of some games,new or old.There are some games where every idiot can rip the music,but that doesn´t apply to every games.Especially those from bigger companies.Some even crash without the proper datas in place - which means you have to reprogram some lines of the code,which leads to re-tests and if the original datas are lost (and thats more then often the case) it could end up being a pain in the arse.
Lets take Burnout Paradise for example: The game data is stored in a bunch of containers.You have 40 Music Tracks and one has to be removed.You got to get to the core data (you got to rip it from the original game),remove the song,remove it from the Ingame-playlist,remove it from the credits and every other clue that it was in the game.If it was played during special game-events you got to find a track that fits (maybe having the same runtime),reconsider every line of the Radio Moderator....it´s not like every game has a simple Playlist.
So saying "it isn´t hard" is a bit shortsighted.
The reprogramming alone can run into other legal issues,since it could be considered a re-release it doesn´t have to cover some other licenses too.
As I said: In most cases it is not worth the effort.

@alaannn: As someone who got some insight in Game-development I can say: No,that isn´t easy.It depends on the data structure and the impact on the game itself,which could be fatal if its not reprogrammed...which alone costs a lot of money if the original Devs are not around anymore.
2000$ is only the Re-rating by the way - publishing costs may be carried by MS but if you got to program anything and still want the game to have a low price its not really worth the effort for a game that almost nobody will care about.
A HD-Remaster of a AAA-Title whould cost around 10K-50K and be more profitable since it gets more attention.

@alaannn: Well,you can look around the Internet,the rating alone of PEGI/USK costs around 2000$.Matters how it is considered. A AAA-Game maybe has a chance to be sold egnough,but in most cases it will not be worth the effort.
.Don´t forget: They got to reprogram a game which original data may be lost and it is not as easy as it sounds to just rip out some parts.

@alaannn: As I said: Its expensive - expensive egnough that some Devs didn´t even release some games for the Wii U on Nintendos Marketplace in Germany for example because it wasn´t epected to be worth it.
So overall the got to reprogram the game,need new expensive contracts,pay a lot of money for a re-release and can´t expect to get anything out of it because only a small amount of people whould care.
If that all is possible MS whould take the effort for their own Games,hey they even pay the whold development of the emulation which isn´t cheap, but I think that can not be expected from other companies.Those companies whould rather do a HD-Remaster,if the original data is still aviable (and sadly it is often not the case) and make more money with it.

@alaannn: Nope - they have to give it to external companies to rate it.Thats expensive and without it they can not even release the game in most countries,including their own online marketplace.

@alaannn: That whould be extra work,more extra cost and a new release, including Ratings (ESRB,USK)...which means the Games could not played in LAN with older consoles,they get much more expensive and - in most cases - not worth the effort.

@alaannn: That is not always that easy: Some want (of course) Money,other had Artists who changed the Label and took the rights with them.

And then there are cases where nobody knows who got the rights - the planned new Turrican for example took Musician Chris Hülsbeck almost forever to find out where they went after the original Company was a goner because they were just a part of bigger deals.