Correct. Because much of WP lives on dynamic output, adjusting themes without recreating the entire site, etc.
I've seen a few people discussing working on a static html 'capture' thing, don't know if anyone did it yet.
Staticize Reloaded is the grandfather of WP-Cache2 -- it caches the content at a given URL for a certain period of time (or until somehow declared 'stale'), as a php stream that can just be reoutput without much overhead. However, unlike completely static HTML, you can still embed dynamic php code in the generated wp-cache'd output, so that certain parts of the page generation remain dynamic.