Knowledge doesn't stay together
Organisations rarely lose knowledge all at once. They slowly lose the places where it used to live.
Knowledge rarely disappears at once. It separates.
A customer explanation remains in an email. A rule survives in a ticket. A workaround stays in somebody’s notes. The original reasoning reaches an ADR, while two colleagues remember different parts of the story.
Each piece still exists. The connection between them does not.
As a product grows, answering a question depends less on recall and more on reconstruction: finding the pieces, deciding which ones still apply, and working out how they relate.
This is why a document alone is not organisational memory. Memory is the network that allows a team to bring scattered evidence back together. A document is useful when it strengthens that network—when it names the decision, points to its source and makes the next place to look visible.
Organisations do not usually forget everything. They lose the ability to assemble what they already know.