I remember learning CSS in the early 2000s, with the book showing how one could have separate stylesheets for on screen display vs printing. You’d think this approach would have aged nicely, now that websites need to render on a large variety of screen densities/sizes/aspect ratios/etc. Well no, now we have huge bloated CSS files full of media queries and weird things that are impossible to make sense of unless you’ve spent a few weeks in the codebase.
So yes, nice in theory but completely outdated in practice given the horrible Beast DOM has become.
Perhaps that approach was too idealistic all along, and only sort of worked in the beginning, when the web was really basic and most people were on a 1024x768 display. The form is the function and also the medium and the message, and it’s impossible to place abstract boundaries on where the content vs presentation vs interaction lie.