The argument of "coding speed not a bottleneck to productivity" is not in contradiction to "productivity is a combination": it even implies it.
Again, the context here was that somebody discussed speed of coding and you raised the point of not using any tooling with Notepad.
I did not raise it, but what was raised was "coding speed": as in, the speed to type code into an editor.
That's not "engineering", but "coding".
Engineering already assumes a lot more than just coding: most importantly, thinking through a problem, learning about it and considering a design that would solve it.
Nobody raised communication or the human factors.
Current LLMs can indisputably help with the learning part, with the same caveats (they will sometimes make shit up). Here we are looking at how much they help with the coding part.
The context here is AI assisted engineering and you raised the point that non-engineering productivity is more important for engineers, which I think is absurd.
You can have 10x engineering productivity boost and still complete work in the same amount of time, because of communication and human factors. Maybe it's a problem, may be it's not. It's still a productivity gain that will make you work better nonetheless.