Ken is one of my least favourite authors on the internet, mostly because he seems to confuse opinion with fact. First of all the article is dated January 2009. As I recall, the first high quality. small carriage photo printer, the Epson Stylus Pro 3800 was released that month and it completely changed the quality of what could be done at home.
Pixels do count more for printing than for what is posted on the internet, so Rockwell's advice is not particularly good for a print maker. In other articles he has dismissed using anything other than sRGB or shooting raw without explaining the advantages and disadvantages of his advice.