By suggesting DITA as a valid alternative to Markdown, for any use, this has so completely lost the plot that it blows up whatever credibility Brian might have on the subject. It's disappointing, because I know of Brian and otherwise respect his work.

Short of writing in raw Postscript, I can't think of a more completely different set of strengths, audiences, and applications. I had to get to a company with more than 5,000 employees, 20 product lines, and 5 required i18n locales to find one where the overhead, god-awful ergonomics, and half-broken tooling of DITA were appropriate for the scale of the work _and also_ resourced enough to paper over every miserable facet of its implementation.

If you're using Markdown today _at all_ for a task, DITA isn't appropriate for it. If DITA was appropriate for the task, you never would've picked Markdown to accomplish it to begin with. Don't waste your time with it either way.