Oh sure. But, then again, what usually happens when someone is wounded? They fall down. Most people who are wounded are only stabbed once or twice. And very few times by someone who is trained in using a sword.
Very, very few times is someone stabbed eight or ten times and then keeps walking around afterward as if nothing happened. Which is what happens in HP.
To paraphrase Gygax, even Conan wore a shirt of mail in battle.
What it means is that the rules of the game must be most suited toward explaining the things that happen most often. Certainly, it's not very realistic for someone with, say, 100 hit points to just stand there and get run through with a sword for 5 damage at a go, until eventually keeling over a few minutes later. But that's also a situation which is highly unlikely to occur within the game, so it's no wonder that the rules don't make a ton of sense for it!
The common situation, which the rules are
actually designed for, have anyone with a significant number of hit points
also likely to be wearing heavy armor! If you hit someone for 10, and that person is only down to 90%, then most of the "stopping power" of your attack was drained into the armor. They covered one hole in the rules by hiding it under a different, tangentially-related rule! (Decades later, World of Warcraft proved that this design philosophy was still around - they didn't want Tauren warriors to be so much tougher than other warriors that it would be unbalanced, but they also didn't want a giant minotaur-person to feel squishy, so they just conveniently prevented Tauren from playing any class that was restricted to light armor.)
So yes, these drastically simplified rules fall apart in situations that are unlikely to occur. Fortunately, it's easy to ignore those situations, because they pretty much never happen. (And if you feel like you
need rules for the unlikely even that someone with 100 hit points is attacked while naked, then that's a perfect place for the DM to interject with a house rule; I recommend that any attack with an edged weapon against an unarmored humanoid is automatically a critical hit.)
You have to be thinking this due to your exposure to very recent history which is tainted by the march of modern medicine; the advent of penicillin to treat infection (post WWI), the development and advancement of field triage protocols, and the advancement of surgical techniques, tools, and technology.
I actually just meant
during combat. If someone hacks at you with a cleaver, you might bleed out in a few minutes/hours or die from infection in a few days, but you're still alive for the duration of combat. Especially in a game of fantasy heroes, where the two conditions are "up" or "down", the natural outcome of being hit with a weapon is that you're still "up" for now. (Plus, see above, concerning the likelihood that you are wearing armor. If you're concerned with modeling non-heroic types, then I believe they call for a morale check when you're wounded or at a certain percentage.)
As a bit of an aside, fantasy settings are kind of a strange place. You want it to
look like pseudo-medieval Europe, but then you can't make it
too gritty, or else it becomes a place you would want to escape
from rather than
to. So you end up with this weird place that has knights and castles and dragons, but also gender equality and (most relevant here) modern hygiene practices.
Wherever you can't explain away something nasty, you just have a convenient herb that happens to disinfect wounds or whatever. (What else could possibly be in a healer's kit?) At least, that's what makes most sense to me. As unrealistic as it may seem, we're mostly dealing with a sort of medieval theme park rather than actual history. Think Velgarth, if you want to see this played straight.
