Landmarks are redundant with native HTML features

The following roles complementary, contentinfo, main, navigation,  
search are redundant with native HTML features and a native element  
corresponding to banner could easily be introduced.

Is there a good reason why e.g. <div role=contentinfo> is promoted  
instead of the HTML-native <footer> element? Exposing either to AT  
should require about the same amount of UA programming work.

For reference, the correspondence is as follows:
complementary: <aside>
contentinfo: <footer>
main: <article>
navigation: <nav>
search: the <form> element associated with <input type=search>

-- 
Henri Sivonen
hsivonen@iki.fi
http://hsivonen.iki.fi/