It's interesting to me that you give a cite for the definition of impetus and then reject that definition. If the fumbler who had position places the ball down on the ground so it is motionless, the ball has zero momentum. A player who dives for the ball and casues it to squirt away, even if he is on the opposing team, has given the ball momentum. He has provided the impetus.
ML/NJ
Or are you arguing that in a "fair" world with perfect "justice" the play should have resulted in a touchback?
I and others have given numerous reason why, in the realm of "fair" play, the play must be a saftey and not a touchback.
So are you just arguing about the technicalities of the rules and what "impetus" means?
Are you arguing the letter of the law or the spirit of football?