Role-playing games are not about storytelling
That is to say, they are sometimes about storytelling, but very often they are about other things instead.
Sometimes they are supposed to be more like a game of Runebound or Waving Hands or some other set-in-a-fictional-world board game. These games still have stories to tell, the same way we might tell ourselves stories about what is happening when we play a game of Chess, or Candyland. These stories, however, are not the point of such games except inasmuch as one chooses for them to be in a sort of existentialist radical-freedom sort of way. In any case, games like this (e.g. 'the dungeon game' version of Chainmail that eventually became D&D, the Cheese Grinder) are not "a group of players gather to tell a story" except inasmuch as that also describes football.
Sometimes they are about characters. Character-driven fiction is very much not story-driven fiction! Examples of systems compatible with character-driven fiction are FATE (that's FATE 1.0 and 2.0; the later editions are exclusively narrative instead) and Dogs in the Vineyard. Character-driven fiction is sometimes compatible with written media, so there are books and novels and such that are good and that are more an examination of their characters than a 'story'. Character-driven fiction does still suffer from the examples you give, but other examples of ways RPGs often have 'not good story mechanics' (e.g. running scenes in which nothing happens that moves the plot-- especially running scenes primarily narratively consisting of quotidian things that are entirely unrelated to the plot, rewarding/requiring 'my guy syndrome') do exist and distinguish the two.
Sometimes RPGs are about stories, but they're about stories about 'what would really happen', motivated by the same concerns as Realist Literature. "and then they were abruptly knifed by strangers" may absolutely be how the story ends in such a work, depending on the setting and the nature of the fictional reality. The ultimate end of systems desiring this sort of thing is an evolution towards a more-complete Pheonix Command, but there are a number of steps along the way as one desires more and more realism at a higher and higher cost to everything else.
Sometimes RPGs are about the story, but they're about the actual story-- viz. the neuro-physical act of story telling. They're about the actual words said by the players, and seek to encourage them to flow well, to establish rythym, to weave and bite back and forth and to be suitably dramatic. The story is the telling, and telling shapes the emotional experience as it happens. Polaris is an example of such a game, with each action requiring the use of a ritual phrase and, when things run properly, nothing interrupting the back and forth flow of description and demand and dialougue. There's no 'roll to see if you hit', no separation between the progress of the narrative and the actual utterances of the participants. Dying in the middle of the night at the hand of someone you wronged in such a game is not 'silly'-- it's a very likely way to meet your end on account of how it's easy to end up in such a place that it makes emotional and linguistic sense to offer such a result within the flow of the narrative.
Sometimes they are not about stories, but just about experiences, the same way a poignant painting might be, or a work of modern art. Such art-games include almost all role-playing poems, as well as some longer works like The Quiet Year and The Dark Forest. I've not seen one in which handwaving off a character via death by roadside bandit makes sense/is possible but I'm sure several exist. In any case, the story, such as it is, is not relevant.
Even in games that are truly about cooperative storytelling and indeed seeking to provide heroic narrative arcs of the sort found in plays and operas and novels and comics and songs and whatnot, wherein the random and absurd death of a protagonistic force is indeed unacceptable and consequently in which it is foolish to use an 'objective', as you term it, combat system there is little reason to expect advice applicable to literature to apply. Just as when you make a movie from a novel or novelize a movie, misapplying the rules and conventions and techniques of one medium to another makes for, frankly, garbage. There are good movie adaptations of books and book adaptations of movies, but there's a reason such works are widely viewed with extreme suspicion and the absolute lowest of initial expectations. RPGs are a medium in which one can create literary and other sorts of art. They are not, however, books nor comics nor (usually) games nor oral storytelling. They are their own thing, with their own limitations and advatages and conventions and sorts of stories they excell at telling. So even though this particular thing is true for some RPG stories, you should not expect a writer's forum answering questions about writing to be applicable in general.
Lastly, this particular quandry-- the conflict between someone hyperprioritizing narration in a format where the audience participates in an open-ended manner-- has spawned an art-game video-game unflattering of your general position called The Stanley Parable, which you may enjoy/find educational. If you're interested, you find it here or just google a let's play.
