The underlying mechanism is still the same: humans type and products come out.
So something which must be true if this author is right is that whatever the new language is—the thing people are typing into markdown—must be able to express the same rigor in less words than existing source code.
Otherwise the result is just legacy coding in a new programming language.
> must be able to express the same rigor in less words than existing source code
Yes but also no. Writing source means rigorously specifying the implementation itself in deep detail. Most of the time, the implementation does not need to be specified with this sort of rigor. Instead the observable behavior needs to be specified rigorously.
> Otherwise the result is just legacy coding in a new programming language.
And this is why starting with COBOL and through various implementations of CASE tools, "software through pictures" or flowcharts or UML, etc, which were supposed to let business SMEs write software without needing programmers, have all failed to achieve that goal.