Structure, design patterns, software architecture, systems engineering, optimization (not of the LoC but the system), data accessibility (in structure as in implementation like indexes etc)... those are the hard ones that require engineers to design and implement properly.
And that’s only going to be more as it’s not the 20 medior SWEs that throw together a full stack application in two days but the untangling of AI slop as the architecture wasn’t built for hundreds of concurrent users