The thesis in the title makes no sense. There really isn't anything so special about the D&D systems that mean one person working from home couldn't come up with an artistic competitor. You don't need to spend any money on TSR books to run a campaign if there is an imaginative DM handy. The only reason D&D is so big is that the profit lets it advertise and have a presence, so more people know about it. That is a beni…
Play was all DIY and the saddle bound Guides were ambiguous suggestions and a gateway into the world of more-than-six-sided dice.
Advanced D&D was a different game sold at the Dalton's in your local mall. Each of the ever expanding line of hardcover rule books - that game had rules not guides - cost about double the ten bucks of the old three guide boxed set (Chanmail was another ten bucks).
My understanding from the article is that the book covers that transition or succession or whatever from guidelines to rules. From a stapled 'zine to manufactured product lines.
Is that the death of art? As such reports tend to be greatly exaggerated, probably not. But there was a change. The game got canon.
And cannon canon https://www.dandwiki.com/wiki/Cannon