HyperCard, Dreamweaver, InDesign, Photoshop, Flash and Illustrator do not use a markup language internally. As with Web Assembly, it's important we have the right primitive that we can compile to. There are configuration languages that can make it easy for beginners to hand edit a frontend, and in my article I mention the configs that Ruby On Rails, Symfony (PHP), and Django (Python) offer to generate simple CRUD interfaces, and I mention that these configs could be much more powerful if they had the correct primitive to compile against, rather rendering to HTML/CSS.

Aside from all that, I would raise the more urgent question for our industry, why did it seem like such an urgent task, all through the 1980s, 1990s, and early 00s, to create visual software that would make it easy for beginners to create software, and yet now this is no longer a priority? Is there some reason why we are moving away from the era when "Empower the masses to create software" seemed like an important goal for the industry?

You can't version control whatever binary format InDesign uses. Markup languages benefit from precision, readability from an editor, easy integration with other tools.