I've worked with employees distracted by kids. Distracted by substance abuse. Distracted by mental illness. Distracted by video games, TV, something on their phone, or even just a basic disinterest in the job.
When we talk about the job market as a whole -- such as in the article above -- it doesn't help to focus on a hyper-selective section of capable, skilled software engineers. The vast majority of workers are in a much messier, less efficient and effective environment.