This is true; as smarter people than me have said, software engineering is programming over time, and that time aspect involves individuals knowing less and less of a codebase. But that's what these smart people are advocating, in order to keep code maintainable, you need to stick to some rules, processes, patterns, etc.

Whether you apply those things to other developers or LLMs is a bit moot I think, ultimately neither (or you yourself) can be fully trusted to know and understand the full system.