I wrote a static page publishing system in the mid-nighties. They're harder to do than dynamic based systems -- calculating which pages link to a given page and need to be updated, say when a title changes, is a pain.

I think static page based systems are needed less now due better hardware performance and the introduction of memcache.

That said, static page systems are very reliable. Even when the CMS goes down people still get content.

If your site is small enough to export the whole thing on every update there are systems such as Jekyll and Hyde.