I have Steam, a Mac, and I own the Deluxe edition of Civ 5 that I got for Windows, so I thought I'd go digging around to see if I could find the soundtrack.
The directory you mention on my install contains a Soundtrack directory, in addition to Sounds, Gameplay, Behind the Scenes, and the Babylon Expansion files.
/Users/{username}/Library/Application Support/Steam/SteamApps/common/sid meier's civilization v/Assets/DLC/DLC_Deluxe
You might try right clicking on the game in your Steam library, and then click "View Downloadable Content" to see if you have "Civ V Digital Deluxe Content (Mac)" as one of your DLC packages. I pre-ordered the Deluxe edition for Windows, and got the Mac version via SteamPlay after that became a feature of Steam, so that might be a factor.
Previously I found another method of extracting the soundtrack, which you can find below:
I checked around and I found this thread on the Steam forums. It appears to have a sections of interest:
You can access the soundtrack files directly from the game contents. Mine were here:
/Users/{username}/Library/Application Support/Steam/SteamApps/common/sid meier's civilization v/assets/Sounds/Streamed/Music/
You'll have to use the Finder to get to this directory, and then you can copy these files out, which are in .ogg format.
If you have up to date video drivers, then the most likely cause is a bad civ 5 install or bad Steam data on Civ5. I've had this sort of issue with Steam before, just not on Civ5 specifically.
- First order: make sure you have latest drivers.
- Second order: Verify integrity of Civ 5 installation via "Verify Integriy of Game Cache".
- Third order: delete Civ 5 off the box, reinstall from Steam.
- Fourth order: copy SteamApps data to temp space, delete steam, reinstall steam, copy SteamApps data back.
That's all the steps I've had to take in the past to get a broken steam game working. If none of this works for you, sorry, but this list has been all I've ever had to perform. Although I have had to do the first and second options repeatedly to fix a game.
Best Answer
The base install is covered by the CD contents.
The game will need to download extra update data from steam though (E.g: patches, updates or any compatibility updates for any DLC, etc.)