alt Hacker News> narrative information through sequences of knots
It's unlikely any complex narratives could be encoded there, though.
Possibly a bit like the e.g. the Mycenaean Linear B script. Which is fully decoded and well understood. But despite having a full fledged writing system they mainly used it for accounting and such. They can tell us about how many goats, sheep and various good they had they had but don't tell as much about the society or history as such.
Heculaneum manuscripts are kind of the opposite from the Quipu in the sense that we have zero issues understanding the actual text/symbols just extracting them from the destroyed scrolls is rather complicated.
Minoan tablets are maybe a bit closer and little progress has been made there (then again we are fully capable of reading the script just have no clue about the language it was written in).
I agree with your point about the Heculaneum, but my understanding is we're far enough with research into the form of the Quipus to know that they aren't simply either a linear script or merely accounting data.
For a long time, it was thought that they indeed contained only the latter, but my certainly non-specialist grasp on the matter is that we now know they were used to encode much more than that. In addition to being used directly to verify calculations [0], they contained "histories, laws and ceremonies, and economic accounts" or, as the Spanish testified at the time: "[W]hatever books can tell of histories and laws and ceremonies and accounts of business is all supplied by the quipus so accurately that the result is astonishing"[1]. My---again crude---understanding is this was through embedding categories, names and relational data in addition to numbers, signaled not least through texture and color [2].
I likely come across as if I'm trying to over-inflate the Incan knots, but really it's just to say they appear to be a rather fascinating in-between of legal-administrative inscriptions, whose discovery transformed understanding of Roman institutions over the last century or so, and the straight-forward manuscripts of the Herculaneum.
[0] My elementary and probably out-of-date recollection: an emissary would come to towns with Quipus containing work orders, which would be validated with the community on the spot.
[1] https://www.jstor.org/stable/27087183
[2] https://read.dukeupress.edu/ethnohistory/article-abstract/65..., https://www.jstor.org/stable/483319