Your essay and this article have been going around and around in my head for a bit, chasing each other. At odds is the idea that commercialization was inherently a bad thing for D&D. D&D is more popular than ever, and inspiring more people than ever. And not just to play it, but to hack it, take it places not intended (I'm reminded of the person that used the D&D Next rules to run a Downton Abbey campaign). And even if you don't do any of your own customization of the game, it's still inspiring people's art and creativity. People make art, music, cocktails, stories, and more inspired by D&D. Even if you run a bog-standard fantasy world, you're still creating.
Yes, D&D was raw and broken when it first came on the scene, and inspired people by dint of people needing to do their own game design to get it running. But as you said, it's never stopped inspiring people and acting as a toolkit. I get that it's also important to support indie RPGs, but contrary to what that article says, D&D still continues to bring joy and inspire.
To be clear- I don't think commercialization is a bad thing!
The obvious benefits include, for example, the fact that it can spread to a much, larger audience. I am truly grateful that D&D maintains those norms that include using it a toolkit, and I am always amazed and impressed with what the people are doing today- the only way for a game to truly be evergreen is for each generation to make it their own.