In what sense is an Observablehq document without the editor GUI the same document? Isn't the whole point of Observablehq that your computation reacts correctly to modifications? Maybe I'm confused about which part exactly is free software and which part isn't, and I should try self-hosting some documents.
It's good that you're aware of the basic aspects of the archival problem, but you're mistaken about the role of digitality — being digital makes it possible to copy documents losslessly, thus preserving them even when the original substrate is lost. That's the reason that, for example, the older books of the Tanakh survive from that time in some form, even though they weren't carved into stone: the alphabet is a digital technology, not an analog one, enabling verbatim copying. So digitality is an advantage for archival, not a disadvantage. (You alluded to the survival of the Tanakh in your comment, so you know about it, but somehow you got its significance backwards.)
Media longevity and interpretability are, as you say, important problems. They require significant engineering effort to solve. Also, it is possible to engineer ways to sabotage media longevity and interpretability, thus greatly reducing the chance of archival success. Making your documents' interpretability conditional on the survival of a mere commercial interest is a good example of such archival sabotage, as many authors and historians have discovered, to their sorrow, in the Geocities era.
I have the sense that you're not seriously engaging with the problem, but rather looking for a quick dismissal, so you may not be interested in the following:
It's relatively straightforward to micro-engrave megabytes of programs onto copper, glass, silicon, nickel, and similarly stable materials, which will easily survive for a million years. Gigabytes are more expensive. Clay and stone are also pretty easy, but with the straightforward fabrication techniques, they have lower data capacity because of their grain structure. PET is commonly used as an archival material, and should easily last longer than paper, but it's less trustworthy — its combustibility in air means that a PET-air system is merely metastable, not stable, and the timespan of that metastability could easily be much less than that of glass.
But even old hard disks could easily have media longevity exceeding the mere 3000-year timespan we're talking about.
I wasn’t seriously engaging because I didn’t take your comment about ancient civilizations to be especially serious. I don’t believe micro-engraving to be a serious long-term archival plan for individuals; if the metal plate (or whatever) gets lost, buried, melted down, ... then it doesn’t really matter what is engraved on it. Very few works are going to be copied as widely as a foundational religious text. If you want your code to survive the best bet is to get it inserted into Linux or something.
(Previously I was talking about e.g. the Rhind Papyrus, not the Hebrew bible, but anyway...)
As for Observable: you could relatively quickly and straight-forwardly build yourself a mediocre version of the editor interface. It is quite likely that if the platform becomes extremely popular better archival solutions will be found. Being an early adopter of this kind of technology involves a bit more risk, especially when there is a business involved, but even when there is not. Plenty of open source file formats are now extremely inconvenient to use.
Oh, I thought you were talking about the Hebrew bible and a few other books because of your remark, "some written books repeatedly copied by generations of scribes have managed to survive." The Rhind Papyrus survives in the 3500-year-old original, including its non-digital aspects; although it is a (digital) copy of an older book, no other ancient or medieval copies of that book or of the Rhind Papyrus itself are known.
Micro-engraving is definitely feasible as a form of archival at the individual level; the engraved text will survive being lost or buried, though not melted down. Given the relative ease of micro-engraving many megabytes, though, it might make more sense as a collective project. 1200 DPI is two gigabits per square meter, and engraving a square meter of material is a lot less work than writing 300 megabytes of even prose, much less working code.
But making Lots Of Copies does indeed Keep Stuff Safe, which is why I was puzzled that you seemed to be dismissing that route in your original comment. But you can do both! Media longevity is entirely compatible with mass production. And later copying is necessary for long-term archival, though not for such short timespans as the ones we've been discussing. Media longevity is necessary to bridge the gaps between periods that are politically favorable for archival — the tragedy of the Maya codices and the khipu is due to a politically unfavorable period.
We don't have a lot of information about what the next 3000 years are like, but with modern machinery it's relatively straightforward and affordable to produce sub-gigabyte-scale archives that would have easily survived short periods like the last 3000 years, even without copying. If Ahmes had had FIB etching, we wouldn't just have his algebraic and geometric algorithms; we'd know all the 12th-dynasty celebrity gossip about which court eunuchs had crushes on which priestesses. There aren't many people working on archival media because product-market fit is really elusive with a 3000-year-long feedback cycle, although Norsam at least has an available product, though at a price point that discourages mass production.
Thanks for the information about Observablehq! I'll definitely give it a try.
It's good that you're aware of the basic aspects of the archival problem, but you're mistaken about the role of digitality — being digital makes it possible to copy documents losslessly, thus preserving them even when the original substrate is lost. That's the reason that, for example, the older books of the Tanakh survive from that time in some form, even though they weren't carved into stone: the alphabet is a digital technology, not an analog one, enabling verbatim copying. So digitality is an advantage for archival, not a disadvantage. (You alluded to the survival of the Tanakh in your comment, so you know about it, but somehow you got its significance backwards.)
Media longevity and interpretability are, as you say, important problems. They require significant engineering effort to solve. Also, it is possible to engineer ways to sabotage media longevity and interpretability, thus greatly reducing the chance of archival success. Making your documents' interpretability conditional on the survival of a mere commercial interest is a good example of such archival sabotage, as many authors and historians have discovered, to their sorrow, in the Geocities era.
I have the sense that you're not seriously engaging with the problem, but rather looking for a quick dismissal, so you may not be interested in the following:
It's relatively straightforward to micro-engrave megabytes of programs onto copper, glass, silicon, nickel, and similarly stable materials, which will easily survive for a million years. Gigabytes are more expensive. Clay and stone are also pretty easy, but with the straightforward fabrication techniques, they have lower data capacity because of their grain structure. PET is commonly used as an archival material, and should easily last longer than paper, but it's less trustworthy — its combustibility in air means that a PET-air system is merely metastable, not stable, and the timespan of that metastability could easily be much less than that of glass.
But even old hard disks could easily have media longevity exceeding the mere 3000-year timespan we're talking about.