Imagine a world where every form of written form - alphabet, books, documents, epigraphs - is gone. I'm thinking about a today-like world, like 21st century western society.
The reason of this happening is not important. I plan to write a post-apocalyptic story with all the cliches (wastelands, tribes, dog-eat-dog mentality, etc.) with this specific added feature. The cause of catastrophe is not important: it's something external to society, so an incident and not a choice. It's also metaphysical, so nothing physical such as reduced mental capabilities, memory erasing, diseases, etc. Let's say that in 30 years after the "apocalypse" ALL people progressively lose any capability to write and understand written language. People cannot read and write anymore. Books have been destroyed, marble writings destroyed, nobody knows any alphabet anymore and the few documents left are unreadable, like hieroglyphs.
How would people adapt? Oral culture will be dominant, of course, but what else could happen? In a sort of post-apocalyptic scenario, where the fabric of society and economy is destroyed, would this be a meaningful problem, or will it be just a minor consequence?
NOTE: this is not a question about how to write a similar story and which language to use. It's just about the perspective of the survivors.