One thing worth mentioning is that even before AI only some small subset of engineers have experienced building systems from scratch or inventing new ways of doing things or root causing complex problems or even writing a lot of code. Most software engineering is maintenance or mundane or not productive.

Even in a world where there's a lot of AI generated code there can still be people that have enough exposure to doing hard things. Definitely at this point in time where AI can't really do all those hard things anyways - but even after it'll be able to.