> we do in fact have worse memories than scholars during the Middle Ages.

I wouldn't be so sure. People can regurgitate from memory dialogs for entire movie series, TV shows, and countless songs. We also remember deeply nested folder structure on numerous computer systems, variety of software interfaces (e.g. click Menu > Tools > Options...), and innumerable memes/facts/lists. Sure we forget a ton (is it needle/haystack or haystack/needle?) but we know and remember a lot more than medieval epic poems.

Navigating the modern world requires an insane amount of memorization but since we no longer need to remember road signs or phone numbers, we feel we remember less today than decades or centuries ago.