[ahnick]

This happens even today. If a knowledgeable person leaves a company and no KT (or more likely, poor KT) takes place, then there will be no one left to understand how certain systems work. This means the company will have to have a new developer go in and study the code and then deduce how it works. In our new LLM world, the developer could even have an LLM construct an overview for him/her to come up to speed more quickly.

[stoneforger]

Yes but every time the "why" is obscured perhaps not completely because there's no finished overview or because the original reason cannot be derived any longer from the current state of affairs. Its like the movie memento: you're trying to piece together a story from fragments that seem incoherent.