Most times that person not preparing the call with an agenda is told in the middle of the meeting that he should have invited someone else that has knowledge on some key point and it ends up needing another meeting to be scheduled. With more context, people may have told him prior to the meeting that person needed to be included to.
Yeah, this is one of the more common failure modes. One meeting wasted, and possibly lots of time lost when the next meeting can only be scheduled much later.
All easily preventable if the person organizing the meeting prepares for it, and shares a brief agenda so that other participants can prepare to, or find replacements if they themselves are the wrong person for the meeting.
