But we aren't talking about most people, most of the time. We are talking about the heroes. And the heroes find a way to live!
I don't care how heroic a PC is, if they bite off more than they can chew, they are going to die.
Wait - is your argument now that his injuries shouldn't have killed him? That those kinds of injures don't represent enough meat damage to actually down a person? Because if those kinds of injuries don't represent enough meat damage to down a person then we all have 1000 hp!
No - my argument is that it isn't necessarily just the quantity of wounds (i.e. how many hp you've subtracted from your total) that may or may not kill someone; it is the severity of each wound and where it is located in combination with quantity of wounds that will do in a PC (e.g. taking 1 hp of damage is a scratch for one PC but a serious wound for another PC)
In the real-world example, each of the wounds suffered by MSgt Benavidez acted to reduce his combat effectiveness, but each was in and of itself not enough to kill him outright. The severity of each of his wounds wasn't enough to cause him to go into shock and fall over, but they
did cause him to lose consciousness on several occasions. Had he not then gotten medical attention, he would have died.
Just hp alone doesn't fully represent the ability to take a massive amount of non-incapacitating wounds, a single wound that is instantly lethal, or a combination of wounds that will eventually prove lethal without medical intervention. An ancient red dragon does 26d6 fire damage. A failed saving throw is meant to indicate you didn't get out of the way, so you are taking the full blast. Best case, your DM rolls all ones. Worst-case all 6s. Average damage is 91 hp. That's enough to outright kill (again using averages for hp) a fighter up to 7th-8th level just as easily as a fighter of 1st level or a 0-level commoner. Why is that attack treated exactly the same as a series of physical attacks with a sword? They both subtract from hp and if you cross that 0 hp threshold, you suddenly go from 100% to 0% and go unconscious? Sure - a single attack that drops you to 0 hp (or even more all the way to negative max hp to kill you outright) is modeled just fine. A series of attacks that slowly subtracts your hp
with no effect until you hit 0 hp and suddenly go unconscious makes no sense whatsoever.
People in fights (boxing, a street brawl, a firefight) become fatigued from normal exertion during the fight and the reduction in combat effectiveness is determined by how well conditioned you are (which determines how quickly you fatigue and to what level). Wounds increase that fatigue. More serious wounds can do things like sever ligaments and tendons, making it so you can't run or hold a weapon (reducing combat effectiveness). A head blow can cause a concussion. A kick to the groin is gonna stun
any human male. All reducing your effectiveness in combat without ever going unconscious or being killed outright. Get slashed or shot multiple times in limbs or your abdomen (and not nicking a major artery or vein) and it might not cause you to be 0% effective right away, but as the fight continues, loss of blood
will cause you to slow down, lose combat effectiveness, and eventually pass out and die of blood loss.
Basically - a series of wounds that
doesn't cause significant blood loss or damage to your central nervous system will slowly lead to fatigue, shock, possible unconsciousness, partly offset by adrenaline levels, general physical fitness, and mental stamina. Cause significant blood loss or CNS damage and its a quick ticket to the dirt nap.
D&D doesn't model this well at all using just hp.
One can argue that cinematic combat is better. One can argue that "realistic" combat is better. There is no reason why you can't have both in the same rpg.
Another rpg system I'm familiar with uses hit points that are solely based upon their equivalent of STR and CON. You don't gain hp as you gain experience. They use multiples of this as a set of trip points. Do 1 hp of damage and you have a slight wounds. > x hp damage = moderate wound, etc.
Each attack is compared to your hp, but hp do not get subtracted from your total. You have 10 hp (for arguments sake, the multiples are 1, 10, 20, 30 hp) and the orc's sword does 12 hp of damage? You have a moderate wound. Shot with a magic missile for 1 hp? Slight wound. Take another hit for 15 hp? You have a 2nd moderate wound which bumps you up to a serious wound.
Each wound level results in certain penalties to your actions, and the chance of going into shock or bleeding out. Of course, that other rpg uses hit locations as well, so a wound to your arm that would cause you to drop a weapon, could cause you to go into shock if hit in the chest, or go unconscious if hit in the head.
Still quite cinematic in play, but much more closely models the effects of wounds on your physical and mental state.