Software engineering is all about making sure the what actually solves the why, making the why visible enough in the what so that we can modify the latter if the former changes (it always does).
Current LLM are not about transforming a why into a what. It’s about transforming an underspecified what into some what that we hope fits the why. But as we all know from the 5 Why method, why’s are recursive structure, and most software engineer is about diving into the details of the why. The what are easy once that done because computers are simple mechanisms if you chose the correct level of abstraction for the project.