[mattmanser]

If you step back you'll realize these are all failures of HTML and the latency of networks that we have to work around, not requirements.

For caching, why do I have to reload a whole page just to change the article part? The HTML 'it's a document' obsession and terrible DOM model that took so long to be updated.

Why don't I define a high level presentation document and then sub-documents? Network latency and the total bizarreness of CSS selector priority.

Screen size. Why can't you dock elements on a page like form based programming language for the last 10/15 years? HTML doesn't have the ability.

And as for accessibility? If accessibility is taking hints from markup about how to present the page, in reality the mark up is tightly coupled to presentation anyway. Accessibility is tightly coupling the markup to the presentation, what it really means is screen readers can format the content nicely without the need for a style sheet.