Fair enough, I misremembered.You misremember.
I want to regard HP as the latter, but they are prevented from being that, because the game rules hard-block it, even if you don't regard them as "physics" that apply off-screen, they do apply on on-screen, and they prevent stuff that's a really, really basic component of really common fantasy settings, like uncontrolled falls killing or seriously injuring people, or people being knocked out or killed in a single blow. The fact that in D&D, all on-screen combat is weardown combat, and that there's basically a trinary state of being "basically fine", "dying" and "dead", with no injuries, and immediate returns to full effectiveness on the slightest healing, and where one night's sleep will fix literally anything does limit what D&D can do fantasy-wise, even just applying on-screen (and assuming off-screen things are very different).
This is disingenuous, though it may not be intentional on your part.
D&D was never close to Jack Vance's take in any edition (as has been much discussed), so it's a weird and pointless semantic argument to point that out. The term Vancian applies regardless.
I agree that it's not possible to have a truly universal magic system (god knows people have tried), but I don't think it's remotely true that you can't design magic systems that are broadly generic and whilst they might not be a 1:1 match, are say a 0.8:1 match, whereas D&D's bizarre magic system isn't even going to be a 0.1:1 match with most games. Either using an exhaustion-based or spell-point based system with casting checks and broader spells would get you a hell of lot closer to about 80% of fantasy media.
(As an aside, you could probably have a decent discussion about exactly how to fix this in another thread, because I don't think it would be impossible, esp. as most magic systems in fantasy media fall into about three categories none of which is even slightly similar to D&D's approach.)
Even WWN with it's intentionally-peculiar system at least has a properly worked-in spell-point based caster (and you can bring in Psionics from SWN). You'd have a hell of an easier time running DS with WWN than 5E D&D (indeed I've seen some people discussing how they're doing just that). And WWN isn't a "generic" system, it's a specific one.
GURPS is of course generic, but I will admit, I am drawing a blank of its magic system entirely so can't comment. SWADE's magic system is going to work better for a lot more fantasy than D&D (IIRC, it's been a while).
It's certainly not true to suggest most/all fantasy RPGs have the same issue to remotely the same degree. It's a risible claim that relies on us pretending to be blind to degree. D&D's system is hugely incompatible with fantasy in general because it's so odd.
That said, I disagree that the rules block any such thing.
The rules allow you to do anything you want. Of course, here's the point where you would most likely invoke the ?Oberroni? Fallacy (just because the DM can make the game good, doesn't mean it's good). Let's put that aside for the moment, however, and examine how that approach allows D&D to work for a broader spectrum of fantasy.
Let's assume you want your game to feel like Black Company (lots of death and injuries that are seriously incapacitating for extended periods of time). I want mine to feel like The Wheel of Time (death is rare for important characters, and while injuries can be seriously incapacitating, healing magic usually renders this moot). Maybe doctorbadwolf wants a game like Journey to the West (serious injuries are usually nothing more than a temporary inconvenience for the main characters).
You can make any of those work for D&D.
You would need to enforce those injuries as you see fit.
I could probably get away with using the optional Lingering Injuries system.
doctorbadwolf wouldn't really need to make any adjustments, except to maybe start the campaign at a fairly high level.
Of course, you're probably thinking that you don't want to enforce injuries. Here's the thing though. D&D is a fantasy game that is intended to support a broad range of campaigns. Yes, experienced through the medium of D&D, but nonetheless a broad range.
The sweet spot of grittiness is going to vary by group. Some people love Warhammer Fantasy RPG. Other people (even those who might enjoy a gritty game) find it too gritty. Heck, you're lucky if your group can come to a general consensus about how gritty the game ought to be.
I would argue that a game that intends to have broad utility (which D&D strives for but WFRPG doesn't) is better setting the grit low. It can always be adjusted higher. People have been doing this in D&D for years with things like critical hit and fumble tables. It just makes the game deadlier than default (which is presumably the point).
A while back, in 5e, the character of a friend of mine fell off a cliff (thrown from the back of a giant goat), and the DM called for a saving throw to see whether he broke any bones. He failed and the DM determined that he had shattered his leg. We resolved it fairly quickly with a good heal check and a LOT of healing magic, but it would have taken him weeks to recover naturally, and he would have been hobbled in the interim.
Whereas tearing the grit out of a game like WFRPG would render it basically unplayable, IMO. Too many things interact with the health and injury systems. You'd have to rewrite half the game to make it work, IMO.
As such, I think its a bad criticism to claim that D&D doesn't support a broad range of fantasy as a result of the hit point system (frankly, I think it's mistaken to claim that D&D doesn't support a broad range of fantasy, given my own experience). You can always add grittiness. It's much harder to remove if it's baked in. I'm in no way saying that D&D is the best at this kind of game. The more versatile a game is, the less specialized it will typically be. However, it can do the job, and for a game like D&D that tries to be versatile, embedding grit into the rules would run counter to that versatility.
D&D's broad appeal is in part, I believe, because it's expected that it will be tinkered with to achieve the ideal experience that a given group is seeking. The designers can't provide that, since every group's ideal experience will differ. I'm of the opinion that D&D provides a good place to start. You probably disagree, and that's fine.