It is about feedback-loops. Even well-funded, top-down design is going to have cognitive gaps. Also it needs to be continuous, usage changes, users/people/customer change, features are added. Other tools in outside environment are adopted, etc ... All these need to be continuously evaluated. tested, and reconsidered. Plenty of people in power acknowledge UX to be important enough to "approve a headcount" but it probably is too limited, narrowly focused, and only focused on new stuff.