To be fair there’s no setup that should draw/win 9 vs. 11 in any way imaginable.
True, it is an extreme example. But I just can't see how a guy who is standing off side and then gets directly involved to score isn't influencing the game, or the positions and reactions of the defenders.
There is definitely room to manipulate this rule until it is changed. The most obvious is to play with 10 men and have your striker stand in the oppositions penalty box.
With current day Lewandowski, we might aswell try it!