I don't know what a good site is for this information but you're basically looking for the stat where they break the field into thirds:
So for instance in that example a team had possession in the attacking third for 20.2% of the game.
It's true that the battle in mid-field is huge and a lot of times the goals are scored on quick breaks when the defense is out of position. When teams have time to set up their defenders and midfielders on defense, particularly teams composed of world class players like those in the WC, it's generally pretty difficult for an offense to break them down. It seems to me that fairly even matchups in soccer usually lead to defensive struggles.
If a team is scoring 4 or 5 goals in a match it's almost always because the other team is much worse. You very rarely see something like a 4-4 match, for instance.