The problem is that PDF targets the printed page, while HTML targets screens. PDF does a better job with respect to printing then HTML does for screens, because

The problem is that PDF targets the printed page, while HTML targets screens. PDF does a better job with respect to printing then HTML does for screens, because HTML has been largely repurposed for creating GUIs. Unfortunately PDF are not easily scripted, and HTML has essentially no support for proper printing. And so alas it all sucks.