Yeah notebooks are fantastic tool to show your works to others. But the problem OP staes is that notebooks encourages unreproducible demonstrations. Markdown +

Yeah notebooks are fantastic tool to show your works to others. But the problem OP staes is that notebooks encourages unreproducible demonstrations. Markdown + code cells makes data scientists to think a single notebook file is enough to upload to GitHub. Missing dependancy information and etc as OP states make others very hard to reproduce the notebooks. You can see tons of GitHub repos that have notebooks only and impossible to reproduce out of the box.