I use markdown-clipper for Firefox, it does an OK job but sometimes requires a bit of fixing up. It does not save images, so I have to do this manually; I use VSCode for Markdown, which has an extension for copy/pasting images to Markdown, it inserts a link and saves the image in a subfolder.

A little friction, but if that's too much, then the article is not worth keeping. But yes, someone with the time on their hands could contribute to markdown-clipper, saving images locally.