Because Kodak probably would have scolded him for picking that film in the first place. Line up Portra 160 or Fuji 160....and then do the DR test. Clark would have had an entirely different article then....and it would never be quoted here!
Exactly Kodak do huge amounts of testing on their films, the new Vision line have a tech which pulls a easy 13 stop range, they publish it on their site.
Clark wanted to do a test to prove something, his modus is suspect, pick a high contrast film stock (Velvia and Gold) pitch it against a 1Ds.
Run the 1ds through shadow highlight tools in PS scan the film whoopie we have a win for digital...
You may be partly right that Roger Clark had an agenda to prove that digital exposures are better than film but his error wasn't in his film choice but rather his technique in exposing, developing, and scanning the Gold 200 film that revealed such a narrow Dynamic Range (DR). Jay Turberville, Ed Leys, and myself (all of these forums) started a project to debunk this, various films including Gold 200 and the better films you mention were purchased, the films were exposed to a transparency film Stouffer step wedge with various under and overexposures to reveal the full shape of the two "knees" of the response curves, and the films were scanned by a Minolta 5300 film scanner by Ed Leys, who has a lot of experience in its use. We never completed the project to a state ready for publication, but it became obvious that some sort of procedural errors had been made by Roger Clark.
Our results showed that most colour negative films (we didn't test black and white) have roughly the same maximum DR as limited by their density range, with some slight variations as to abruptness of the "knees". The main difference between the lower quality films and the professional grade film as to establishing a usable rating was just grain size, so typically a higher grade film then looks better printed larger
but the amplitude of variations as determined by the grain variations stays the same . This means that you will always find grain in film if you have the resolution to see it, as the grain variations are much larger than the limits of the DR. This is in contrast to digital images where the noise grain is less than our detection limit and blowing up the images beyond a certain point just reveals their detail limit.
Direct comparisons of film to digital aren't really possible for two reasons, in that digital DR is primarily limited by the "noise floor" at the dark shadow end where as there will be also be a "noise ceiling" for film as one attempts to use the "knee" at the other end of the response curve, and that the "grain"
noise of digital has a fixed size in its native state that is set by the sensor resolution. However, for medium size prints of say about 8 by 12 inches for consumer films or for larger 12 by 18 prints and up from professional film as compared against modern digital equivalents as to consumer and profession DSLR's the output will be very similar with advantages for each. Colour negative film has the advantage of slightly wider usable DR but the disadvantage is that to these print sizes it will always reveal more "grain" noise, even in the center of the response curve but especially as you try to push the use of the "knees".
In summary, my point is that, first, you chose a grade of film more depending on the size of the print you need to make but that it didn't really affect DR much and, second, that film use always shows more grain than modern digital at comparable viewing sizes even though colour negative still enjoys a slight advantage of wider DR over even the best digital DSLR's.
Regards, GordonBGood
) In this light, digital takes a lot of the mystery out of photography. 
