I would argue, though, that base 5e is designed for more heroic fantasy- you're almost always going to live to see another day, absent major screw ups. This is the "whack-a-mole" problem.
The whack-a-mole problem, much like the 5MWD problem, is regarded as such in part because it's at odds with an 'heroic fantasy' feel. The 'heroes' who go out, get in a couple of scrapes, and bed down for the mid-morning to get their spells back isn't to heroic.
While I suppose it might be a little heroic to keep getting up, taking a swing, and getting knocked back down again, it's also more than a little silly. And that's literally what can happen once the support caster in your party has done the math.
A monster drops an ally, the healer uses his lowest-level slot to healing word the ally, the ally totters to his feat, takes his turn, then a monster knocks him down again. Rinse. Repeat. It happens because that's the support caster being played for maximum efficiency. Because of heal-from-0 the caster is forcing the monster to 'waste' all the damage it inflicts on the ally over the little bit he was healed for. Because being down to a few hps doesn't make you any less effective, the ally loses only the movement cost of standing up. The caster is minimizing his resource usage, leaving the ally to spend HD to heal up on the next short rest. It's all prettymuch optimal, and it's pretty un-heroic looking.
Of course, to really 'work' said caster has to go between the monster and you. If it the monster drops you, then you go, then the healer, it's not as clear-cut, healing you could be pointless because you'll just get dropped again before you act. Too bad/so sad, make a death save. ;P
Is it meta to think that in a world with healing a foe might understand that there is "dead" and there is "mostly dead" and "mostly dead" means "slightly alive" and "slight alive" means they are only one ranged heal spell from ganking said foe while they try to focus on the remaining standing foes.
It depends on the setting. In a lower-magic setting and/or one where PC types are very rare, it might be that a bandit or ogre or whatnot may have lived it's whole life and preyed on many victims without once encountering one that would get back up again after being dropped.
That was kinda the default assumption of the PoL non-setting - PCs (and PCs might be the only creatures in the world using PC rules) had bunches of surges and could Second Wind and PC 'leaders' had all sorts of surge-triggers. The general spellcasting that permeated the world was rituals that couldn't even be used in combat. Most NPCs, like monsters, had a surge, and rarely any way of using it in combat. The DM was advised to have most monsters ignore dropped characters as defeated.
Even then, a recurring villain would quickly get wise to the heroes' resilience and might take to putting them down with prejudice when they dropped.
And, there were always hungry ghouls...
