I've been working on the same product for 6 years now, on a team of people who have been working on it for 8 years. It is ridiculous how hard it is for us to design a new feature for the product that doesn't end up requiring the entirety of the deep knowledge we have about how existing features in the product interact with each other. That's not even getting into the complex interplay between the client and the backend API, and differences in how features are described and behave between the client and server. It's, in some ways, a relatively straightforward product. But the devil is in the details, and I find it hard to believe LLMs will be able to build and possess that kind of knowledge. The human brain is hard to beat deep down, and I think it betrays a pessimism about our overall capability when people think LLMs can really replace all the things we do.