Due to the way society progresses, it is necessary to periodically rewrite and reinvent scientific literature to prevent it from becoming anticolloquial (ie within a social sphere not contained within existing society. The Voynich Manuscript is one such example of anticolloquiality). If a civilisation cannot reproduce scientific literature, then it becomes necessary to reinvent it. If it cannot be reinvented quickly enough, such as before technological output requires utilising it to preserve civilisation, then that will likely lead to collapse of that particular system.
As knowledge is lost while we continue to rely on the technology itself, we lose the ability to understand its structure and the purpose of said structure. If an engineer for example encounters design patterns which are arbitrary, complex, or different enough to invoke a sense of alien nature, they may become convinced that the device should not work. This is an implausible design.
When the whole of civilisation begins to rely on an implausible design for some facet of society, the capabilities of that design become streamlined in terms of scientific and folk wisdom. Within that new framing of knowledge, certain tasks which were previously known to be possible with the existing design are lost as well. So these previously-accomplished tasks become implausible scenarios.
Over time, as implausible designs produce implausible scenarios, civilisations continue to record their history in relation to these material and cognitive conditions. Implausible scenarios are proposed as historical events, and over time are rejected despite their truthfulness.
It is very easy to think, "Surely if they had [technology] they would have written about it!" But when institutions collapse and can't continue to produce individuals to maintain the institutional knowledge and the systems themselves, it only takes a couple generations before the implausible scenario is rejected or at least treated as folklore.