That's a fair point, and I'd actually agree with the premise. I work in an environment where the scale makes it impossible to fully understand the full picture, so it's true no single engineer holds the full territory.

But I think the distinction isn't about completeness of knowledge. It's about the feedback loop. Engineers hold partial mental models, but those models are constantly being corrected by reality. You get paged at 3am, you see traffic behave in ways the docs don't describe, you debug something and discover the system doesn't work the way anyone thought it did. Tribal knowledge is actually a good example of this. It exists precisely because someone experienced something that was never captured anywhere. LLMs can't acquire that because they don't experience the system IMO.