Since you seem to be hung up on the narrative aspect instead, the narrative of the resolution is important to how it is played out in the narrative to the players. The narrative is not important to the fortune mechanic of hit points, it doesn't care. The fortune mechanic can be whatever you want (taking the damage, avoiding a lethal blow, etc.). What does it mean in the narrative when your attack roll succeeds against the target's AC? Did you "hit" them? Did your attack "threaten" them? What about the damage? If you do 5 damage to a creature with 20 hp, did you lob off an arm? Gut them? Make them expend a lot of luck to avoid your "hit"? What about when the attack roll fails against the AC? Did you miss them completely? Did you make contact physically but fail to penetrate their armor or hide or even their clothes?
All that matters is that you are in a fight, normally for your life, and when your HP reaches 0, you are out of the fight (i.e. dead in older versions, unconscious in later ones). I say "The fortune mechanic doesn't care how the combat happens, only the result at the end: life or death." and you say "The combat mechanics...in no way guide the narrative...outside of 'you die'."
So, the narrative is important to the players but doesn't impact the resolution of the fortune mechanic. If the narrative doesn't affect how the players feel about the game and the enjoyment they get out of it at your table, that's fine, but it plays a huge role at my table. The narrative is a big part of what makes the game fun.