I read most non-mathematical text in epub (usually converted from something else) because, as you say, it is better. But there is no tool support for making good epubs of math text, so I still need PDFs. When I have LaTeX source for what I read, I just compile with appropriate margin settings.
Really PDF is just ill-suited for distribution of text. The only reasonable exceptions are when that text is explicitly meant for printing (ala fliers or posters), or when said text is not computerized- e.g. a scan of written script that has yet to be OCR'd
Alternatively, provide documents in latex or similar and people can do the final compilation themselves, dictating exactly the details of the physical medium (be that printed paper or an electronic display of some kind) they will be using to view it.
This would require people learning how to do something, though.
