Note: I am not into web programming, so forgive my ignorance in case the question is trivial. Also, please don't comment about "how flawed" the out-of-box comparison of these products is. The question is not about how they compete against each other, rather about the reason behind the incredible slowness of ALL of them.
Just read about a benchmark, where Joomla, Drupal, Wordpress, Plone3 & 4 had been tested. What shocked me is this: out of the box they performed around 4-14 pages/sec. How is this possible, why are they so damn slow? A CMS should just query a DB and churn out the data packed into nice templates. DBs are fast. Templates should be fast (text replacement, no big deal). Our machines are superfast and yet, these high profile CMSs could only produce a few pages/sec. How come?