I mean if the model can reason about making the changes on the large-scale repository then this implies it can also reason about the change somebody else did, no? I kinda agree and disagree with you at the same time, which is why I said most of the engineers but I believe we are heading towards the model being able to completely autonomously write and review its own changes.
There's a good chance that in the long run LLMs can become good at this, but this would require them e.g. being plugged into the meetings and so on that led to a particular feature request. To be a good software engineer, you need all the inputs that software engineers get.