I don't know about this. He admits you can write prototype code with chat-based LLMs, but then says this doesn't matter, because you can't write extremely complex applications with them.
First of all, most people can't write extremely complex applications, period. Most programmers included. If your baseline for real programming is something of equivalent complexity as the U.S. tax code, you're clearly such a great programmer that you're an outlier, and should recognize that.
Second of all, I think it's a straw man argument to say that you can either write prototype-level code with a chat UI, or complex code with documents. You can use both. I think the proposition being put forward is that more people can write complex code by supplementing their document-based thinking with chat-based thinking. Or, that people can write slightly better-than-prototype level code with the help of a chat assistant. In other words, that it's better to have access to AI to help you code small sections of a larger application that you are still responsible for.
I'd be more interested in reading a good argument against the value of using chat-based AI as another tool in your belt, rather than a straight-up replacement for traditional coding. If you could make that argument, then you could say chat is a bad UI pattern for dev tools.