I agree that Markdown is probably an inferior markup format compared to org but serious usage of org is tied to Emacs. Moreover, Markdown (or CommonMark) has an extremely healthy ecosystem and a lot of tools that make life easier, unlike org mode. The most popular static site generators also use Markdown and RST.

Unless using Emacs becomes a user friendly beginner's choice (which it isn't, and that's fine) or Org is able to distinguish itself in isolation from Emacs, I don't see org being widely used anytime soon. If org gains first class support in editors like neovim, vscode and tools like pandoc, mdcat etc, I could see myself using it.