Even still, part of the reason we use css is so we can easily position elements around the screen - and then when the style sheets are detached (by a screen reader or text based browser) it displays inline semantic html with no styles at all. All having a javascript framework to render pages would do is add another step into degrading the site:
(X)HTML -> (X)HTML with Style(CSS) (basic styling) -> javascript rendered css (depending on user agent) OR javascript rendered flash
take for example - sifr which renders a custom font in flash, if the user does not allow javascript/flash then it gracefully degrades to a core font.
http://www.mikeindustries.com/sifr
These types of kits will be what render pages completely top to bottom, whilst keeping things accessible.