Well I think there is a slight advantage to the attacking team, if only a momentary one. I do see the points you are making, not many tries are scored directly from a scrum, that's true, but ground can be made going forwards, and although the forwards are back in play almost immediately, this can still be bypassed by quickly passing the ball out to the wings, away from the scrum.
There must be an advantage, I know if I was running down the pitch, I would rather be facing six or seven players than a full pack of thirteen.
