Most of the people who would buy games like Civilization are PC-oriented, and they probably own 360s (especially in parts of Scandinavia). That said, this game is actually selling pretty poorly and the sales are offset by other purchases Europe/PAL has made.
Second week of Civ: Rev on both PS3 and 360 in Europe: 24,911
Second week of Deal or no Deal on the DS in Europe: 40,983
Now, of course, DoND was launched near the holiday season to a large casual userbase, but that's still bad gaming choice folks.