I’d say Markdown meets every one of those criteria except “more features” (which is a feature IMO) and “easier to monetise” (which is another feature. :D )
To be displayed in a pleasing way to most humans, it’s also rendered as HTML, usually with some kind of styling. In a world without HTML, what is Markdown going to use?
https://en.wikipedia.org/wiki/X_Window_System#History I recall some pdfs of the Xeroc PARC showed more info on it.
Edit: I might have confused LaTex with https://en.wikipedia.org/wiki/NeXTSTEP. I think it was more efficient in handling data, but then again, platforms age whenever a new application needs more memory, so they got abandoned because it was more efficient to bundle it into something like Wayland...
Otherwise the Alto used Bravo and Gypsy for WYSIWYG typesetting: