I read the argument as "the hard part of software engineering is understanding the codebase and the world well enough to turn a description of a desired change in how a system should act into a diff that actually changes the system behavior in the intended way (and only in the intended way), not taking clear requirements and turning them into fresh code".

Of course humans aren't exactly great at that part either. But I do think I'd bet against, within the next 4 years, an AI tool being able to take tickets in the form

1. Expected behavior

2. Observed behavior

3. Steps to reproduce

and produce a changelist that legibly fixes the problem, and does not break anything else, at a level better than a typical junior software developer. I think the ability to do that is probably AGI complete.