That seems like a very narrow concept of "doing" which presumes that writing is an unproductive activity.

This may be true for programmers (whose most productive work is generally unrelated to writing), but is untrue for writers.

I agree, but that's one reason I disagree with the original post, because the two blend together in fairly complex ways. Sometimes, thinking about things, mapping out possibilities, comparing alternatives, etc., without doing any of them, is itself productive. For example, Alonzo Church mostly theorized about what computers could do, came up with a bunch of thought experiments, proved some things impossible, discussed why other things would be possible, etc., but never really got on with the business of actually making computers do much of anything. But that's fine, because his main contribution was precisely the thinking & talking--- giving us a better understanding of what computers could do, not actually making computers do any of them, was his thing.

You could phrase it as "productive talkers", whose talking is important, versus "unproductive talkers", whose talking is just hot air, but that starts to get close to being a tautology: the bad kind of talking is bad.