If the group has been thrown in a pit from which there is no feasible means of escape and they have been left to die, "points of failure" are no longer a concern. It sounds to me like this is describing a campaign end state, not a problem to be overcome.
The way to escape is to get through the door of the cage, presumably. You have created something where there are no points of failure because failure is
guaranteed. I am talking about a perfectly fiction-appropriate scenario, abandoned in a dungeon cell, where failure absolutely is not guaranteed...the problem is that nobody in the party is rolling well enough to get out. So they have to keep rolling and rolling until they get something like a nat 20. Consider, for example, a group made up of a sword-and-board Paladin, a Fighter specialized in heavy weapons, a Wizard (who went for high Int/Con instead of Dex), and Druid. None of them took Sleight of Hand/Thieves' Tools/etc. proficiency, all of them coincidentally have either -1 or 0 Dex mod. Perhaps the GM randomly rolled to determine what kind of lock was present on the cell door, perhaps they thought it was most verisimilitudinous for a dungeon cell door to have a high DC. Whatever the reason, the DC is 20 (a superior lock, per the 2024 DMG). That means this party cannot escape the dungeon until the lock is broken, which would require a nat 20, or something even more difficult (such as breaking through the bars, almost surely a DC higher than 20, which would be difficult even for a party good at Strength things).
It's still a single point of failure, but one that grew out of absolutely no planned story whatsoever on the GM's part. Just "extrapolating" from (a) the PCs got captured by bad guys, (b) the bad guys are temporarily residing in this abandoned castle and don't want to deal with the PCs for whatever reason, and (c) the castle dungeons are still perfectly serviceable as a place to lock up prisoners and then leave when it seems prudent to do so.
The assertion was that a single-point-of-failure situation
cannot occur unless the GM is forcing a specific plot, and thus cannot possibly be a concern in a "traditional GM" sandbox-y game. I gave a quick, brief, low-detail example of how it could happen that a single point of failure would be an entirely verisimilitudinous result
from a game with zero planned story. My only point was that it is false to assume that, because you've encountered a single point of failure (SPOF), you've
guaranteed caught the GM in the act of enforcing a story.
Edit to add: I will agree that it is one situation where it's either forward or stop forever, but it must be built on a whole sequence of events and decisions that led to this point.
Certainly. I'm not claiming that this happens 100% of the time or anything like that. I am simply giving it as a counter-example to the original claim, which was that any SPOF in any game, you've got effectively a smoking gun that the GM is actually enforcing a story on you rather than legitimately following reasonable application of "traditional GM" techniques and the various other descriptions given in the thread.
If this ending isn't acceptable, it shouldn't have been allowed in the first place. As I mentioned earlier, if it was allowed when it shouldn't have been, I don't need fail forward to fix it, I just say, "Hey, it's not reasonable that the party was thrown in the Pit of No Return just for jaywalking, I was meant to say you get thrown in the Pit of the Overnight Stay" or whatever.
But isn't that explicitly interfering with the world in order to create a better story? Like, I specifically constructed this example--even while recognizing that it is not a
likely result--because it was, 100%, completely, in keeping with all prior descriptions of a "realistic" world, of "extrapolating" from existing information, etc. What you suggest here is in fact precisely, diametrically the
opposite of that. It is the GM directly and overtly rewriting the world,
in defiance of the GM's original extrapolating-from-existing-information process, in order for the players to have an actual adventure and not a completely realistic but extremely unsatisfying dead-end.
Further--even if
this situation isn't a problem, what is this "shouldn't have been allowed" thing? By the explicit procedures describd here and elsewhere, the GM isn't "allowing" anything, otherwise they'd be unfairly putting their thumb on the scale, forbidding some outcomes and protecting (or even, possibly,
enforcing) other outcomes, for purposes entirely unrelated to what is a reasonable (plausible, realistic, verisimilitudinous, etc.) extrapolation from what is already known.
I promise, I'm not trying to be a butt about this. It's just really confusing, because I was given to understand that the GM "allowing" some outcomes (and thus forbidding other outcomes) was an utterly unacceptable, completely and totally
wrong act in this context. Something that would majorly upset all or nearly all fans of the "traditional GM" sandbox-y campaign. For you to now bring it up as an obvious thing that has to happen is bewildering, because it seems like you've just rejected nearly every argument previously made by "traditional GM" sandbox-y campaign fans in the thread!
If the PCs have allowed themselves to be captured by Evil Overlord Literally Merciless, with a full understanding of the risks and potential consequences and have failed to utilise any chance of a escape leading up to this point and now they're out of options, then so be it. But there would have been a whole long sequence of events leading up to such a final ending and probably more than one, "Are you sure that's what you want to do?" from me before such a thing occurred.
I just don't think it's anywhere near as unreasonable as you do. PCs make dumb plans all the time (would know, have played many PCs, have made many plans that sounded WAY smarter while we were at the planning stage), and even a good plan can go south because of bad rolls. There's no need for "Evil Overlord Literally Merciless". Just some bad guys who don't want to be guilty of
murder...but don't want the PCs coming back to mess with them again, which seems like a perfectly reasonable thing for SOME bad guys to do. Maybe they even see it as a survival-of-the-fittest kind of thing, that it's a "moral" act (under their twisted sense of morality) to remove the PCs from the gene pool if they can't escape such a situation. I dunno! It certainly seems to me that many, many different entirely-plausible, extrapolating-from-what-is-known situations could result in the PCs getting captured and locked up, and having to break out of a cage, without the benefit of manipulating any guards.