In my experience, the real '10x' productivity bump comes from engineers who can internalize huge swaths of the codebase and make all of the necessary connection

In my experience, the real '10x' productivity bump comes from engineers who can internalize huge swaths of the codebase and make all of the necessary connections. Given a large enough product, that will be out of reach for the majority, due to either dedication or capacity. Hearing about a new feature and instantly knowing the implementation points and consequences instead of having to fumble around parts of the system you're not familiar with is easily '10x,' LOC be damned.