Because you will have an understanding of the complete system. Your domain and the code. This means that you can be more creative with it and also get yourself out of a mess if it occurs (which it will).
From what I have seen AI doesn't understand the code. But even if you argue that it does understand the code it definitely doesn't understand the domain because it's only input channel is a stream of text and you didn't even type in a "full" text representation of the domain.
So you remain the only thing that can understand the whole system. If your competitor has no one (or no team) who can put together a full understanding of the system then you will have an advantage.
What I would love to see is a side by side comparison of two companies (one using AI, and one without) over an extended period of time.
Id wager that they would fare the same. The time saved on some tasks are outweighed by extra time spent on others. Everyone assumes that just because you can pump out more features, you're more successful.
History has a lot to say about the ruling class benefitting from (and ensuring?) the working class cannot organize, because that is exactly when the workers have leverage.
workers that feel powerless and dont try to resist is great news for rulers who only serve to generate revenue.
