Updating is necessary on any dynamic system. Your CMS will be no exception.
With more or different scopes, Plugins are necessary. And yes you can implement all needed Plugins static into a CMS, but then you have to update definitely the CMS with more potential Bugs.
And yes WordPress need better competitor.
And yes, every PHP developer in the last 15 years build his own CMS with staic site generator, without update hassle... because they never update ;-)
