The pandoc repository[1] has nearly 45k stars and 4k forks. It's embedded in Jupyter notebooks, which are used by data scientists the world over. The python wrapper for pandoc has 16 million downloads[2].
[1]: https://github.com/jgm/pandoc [2]: https://pypi.org/project/pandoc/
Next?
But maybe that's insufficient. Hugo[2], one of the most widespread static site generators in existence, supports Pandoc markdown flavors as well as general GFM.[3]
[1]: https://jupyter-notebook.readthedocs.io/en/stable/examples/N...
If you are comfortable calling Markdown a futile exercise in avoiding proprietary control of a universal, simple document format for wide interoperability across natural languages, programming languages, and monopoly interests, then you and I are Microsoft vs Sun over Java in the 1990s.