Why must the PDF encapsulate all requirements? My understanding of accessibility requirements it that you must have a version that is amenable to automatic speech, not that all versions must be.
It doesn't have to. But ideally you only want to have to produce and distribute a single file.
Also, a lot of people don't consider accessibility when generating PDFs. If LaTeX produced accessible PDFs, the PDFs would be tagged automatically without the author even thinking about it. Of course, it might still not be perfect, but it would be a lot better than the status quo.
Also, a lot of people don't consider accessibility when generating PDFs. If LaTeX produced accessible PDFs, the PDFs would be tagged automatically without the author even thinking about it. Of course, it might still not be perfect, but it would be a lot better than the status quo.