The rampant use of Markdown while there's a lack of viewers for it is baffling. And no, I don't count editors in which you can invoke a "preview" of the Markdown. Why publish in a format that must be loaded into an editor and then "previewed?"
You might as well just use plain text, since the reader is just going to be seeing the raw text of the file anyway.
Or have stand-alone viewers (not editors) for Markdown proliferated since I last checked a couple years ago?