That's not true.
If you use MovableType with static content Apache won't have any issues with the traffic
Any WordPress has the wp-cache plugin which lets you set page life and turn it or or off from the broswer.
It is a little silly to compare software performance on the one day it will get slammed by the digg effect, if that ever happens to the site.
I have been impressed with Wordpress hands down over the other blog software I have used. flexibility, community, themes, plugins / extensions. If there is something out there as good or better, nothing has come up with my using Wordpress to make me look.