Can't say that I agree with much of the OP.
I do agree that the "fire and forget" part is nice. Yes, there is an elegance to simplicity. I can buy all that.
However, I find that HP is a barrier to many common tropes:
•Hostage situation? Hostage has enough HP to survive, so no narrative tension.
Depends on the hostage of course but if someone has a knife to someone's throat in my game I use a variation of 3e's coupe de grace. The hostage is considered unconscious which means that the attack has advantage and is automatic critical. In addition in my game if they survive that it's a fortitude save equal to the damage dealt (up to 20).
Even it's a common trope in TV shows and movies to have the bad guy with the gun to the head of a hostage of one of the protagonists telling the other protagonist to drop their gun or they'll shoot (something no one with any training would ever do by the way). The two protagonists look at each other and the captive does something unexpected and gets away with minimal injuries or the other protagonist shoots anyway ... it happens all the time. D&D is emulating fiction, not reality.
•Rushing to save someone from falling off a cliff? Meh, they'll survive the fall damage, so no narrative tension.
After a certain point you aren't going to survive a fall in my game either.
I also disagree with the verisimilitude stance presented, as it conflicts with personal experiences of having found victory in spite of injury.
It's a death spiral and simplicity thing to me. You may have found victory in spite of injury in an encounter. PCs put their life on the line constantly, a death spiral would be deadly and wouldn't work for the game. In addition there are plenty of stories of people continuing to fight despite serious injury, adrenaline is a hell of a drug.
Admittedly my first two are house rules but that's part of the appeal of the game. They are really minor tweaks that make the game work for me.