alt Hacker NewsIt's not that simple. The formats differ structurally. Org-mode is a proper tree - that's its fundamental basis. A tree where each branch can hold k/v pairs of metadata. Markdown is rather a flat sequence of blocks with level markers sprinkled in. Neither of that (proper tree or records) fundamentally supported in Markdown within an agreed spec - pandoc attach attributes on its own way, kramdown does it differently, etc. That's the most difficult part - there's no agreement of what Markdown is - each tool treats it differently. While Org doesn't have a formal spec either, there's no mess, because "the spec" is in the Elisp code it ships with. Even if there's fragmentation (Org-Roam, Denote, howm, vulpea), it is all contained within emacs-land.
If you want to use markdown for Agenda and calendaring in Emacs you'd have to invent a different subset of markdown, most likely poorly supported anywhere else. And if you get there, then it begets a question - why? If we already have something far better and it's called Org-mode?
It would probably be enough if Org files could use Markdown for the free text parts, tables, headings and blockquotes, while keeping Org format for its key-value properties and structure other than headings, when those optional parts are used.
(Though Markdown's inability to nest Markdown inside HTML elements is a terrible default. HTML semantic elements containing marked up text is basically how I write documentation to myself, and obviously the right way to mix plain text-like markup with named, extensible annotations beyond the default syntax.)
I think most of the friction comes because you have to keep converting free text with bold, italics, headings, etc. between the two, costing time when you're moving notes, documentation, README.mds, code comments nowadays in Markdown, etc. back and forth between the two. That creates a dilemma: Should I write README.org or README.md in my personal project? Should I write Org notes about my work to help me track of WIP and notes that might become documentation, or Markdown blocks inside Org, or Markdown notes? What if I'm collaborating with others, or think I might in future? What about collaborating with LLMs?
It's just enough friction that I ended up avoiding Org for organising my work, even though I like the idea in principle and use Emacs all the time.