It seems we have the same opinion of the Northrups .OK, I get what you are saying. And you're right, he never says to increase the ISO so you're left wondering how the hell you can do anything.
As @John King says, this is much too slow to use with normal shooting, IMHO. It wouldn't fit at all with the way I usually shoot (again, similar to @John King it seems) - using Aperture priority and presetting the ISO to what I think is necessary for the current conditions, and then shooting away. However, I DO think it is good to know, and if you are shooting say table-top products or non-moving macro stuff, then it would be a good thing to employ.
While I was reading the article I started to think, "Is this guy a relative of Tony Northrup!?!" It is a bit mantra-like!
When not shooting fully manual, I often use Misomatic mode: manual mode with Auto-ISO. I preset the aperture, the lowest acceptable shutter speed (based on subject, camera shake), and let the camera pick the ISO. The EVF/histogram/blinkies show me if I am in danger of clipping the highlights because of too much light. I wish there was a mode that would raise the shutter speed in such a situation automatically.
Using Auto-ISO in aperture priority mode works often very well, though I lose easy control of shutter speed.