The one thing a static or even a dynamic site has over a blog, is the update cycle. I mean with HTML, once the page is up,
IT IS UP. (unlike some furry folks I know, who get droopy right away

but no names...

) Until you opt to make changes to the content, it is there, for all to see, and admire, and use.
With blogging, there is a constant cycle of 'updates' to either the core files, which with Wordpress is about one major update every four months, a bug update that follows that, then usually a security update right after that. So 2 added core updates, for each main core update.
Confused yet? 
Then there is the theme updates, which until the release of 2.6.2 was pretty well non existent. Now it is also becoming rather frequent, but not as much as the Plug In debate cycle. Why some plugins will update every day of the week for a week, and that is truly a nightmare.
The reason is, that plugins use the core files, use your database a lot, and so any security holes can impact the whole blog. Then too, there is the compatibility issue with the core files, or with other plugins, and that is a hit and miss situation too.
It isn't like they tell you it won't work with this plugin or that one, you just have to keep close tabs on how your blog performs, in order to tell. Unless you get the one that suddenly when activated shows up a whole mess of error notices and no blog.
So if you are looking for an easy ride, by blogging...
GUESS AGAIN JACK. IT AIN'T GONNA HAPPEN.
For the record, most plugin updates are indeed security related, though most claim it is bug fixes. Funny, the plugin works great, but suddenly needs three or four upgrades in a row, but yeah, it is only a bug fix... NOT!
Moral of the story, Choose Your Plug Ins with great care.