Except that the Dobnak thing was explicitly written into the rules for a save. Hitting a home run in a 15-1 game is not the same, because there is no rule for game situation about what constitutes a home run. Saves, on the other hand, are completely determined by game situation. And for some reason, the people determining what constitutes a save decided pitching the last 3 innings regardless of score and performance equals a save.
Even wins can take into account how a pitcher does. It rarely, if ever, happens any more, but the official scorer can take a win away from a relief pitcher who is in line for a victory if he does poorly, and the scorer can give it to the next pitcher who comes in. (Rule 10.17 in the MLB rule book, if you doubt me.)
But the 3 inning save rule has no such contingencies I am aware of...