What are you talking about? No one’s writing their paper in HTML.
The problem is having the submissions be in TeX and converting that to HTML, when the only output has been PDF for so long.
The problem isn’t converting HTML to PDF, it’s making available a giant portion of TeX/pdf only papers in HTML.
If you’re arguing that maybe TeX then shouldn’t be the source format for papers then I agree, but other than Typst (which also isn’t perfect about HTML output yet) there aren’t that many widely accepted/used authoring formats for physics/math papers, which is what ArXiV primarily hosts.
HTML doesn't support the necessary features. Citations in various formats, footnotes, references to automatically numbered figures and tables, I could go on and on.
HTML could certainly be extended to support those, but it hasn't been. That's why we're talking about this.
Did you fully read my comment? Please point me to where HTML/CSS provide the features I listed.
It doesn't really matter if HTML/CSS is more powerful at a hundred other layout things, if it doesn't provide the absolute necessary features for papers.
Citations need to generate reference lists. Footnotes require automatic placement at the bottom of each page. Your examples of numbered tables are numbering the rows, not the tables. And figure numbers need to be referenced in the text.
None of what you're pointing to does what academic papers need. Why are you trying to push this agenda?
That's theory. Can you send me a link to any html file where this actually works? It's a problem I'd love to have solved.
Edit to clarify: The break-after property works with the worthless print dialogues, but doesn't function with "Export to PDF", which is what most people will want to use.
All papers should be in HTML/CSS or Tex then just simply converted to PDF.
Why are we even talking about this?