Research papers are far more complex, and have established standards that aid quick reading and parsing. I absolutely don't want to deal with reflowing equations, reflowing figures, or whatever when publishing papers. Precise margins and column widths.
Responsive webdesign has been around for quite a while. I don’t see a reason, other than lack of effort/investment, why we shouldn’t be able to read technical papers on variable-width screens, in a non-paginated form.
Dealing with the technical challenges should not be the task of the author, but the publisher. And indeed, most publishers are on it.
What‘s missing is a standardised format that can be downloaded, annotated, re-shared like a PDF.