The talking heads point is deeper than that. Not only are they paid to be interesting.

The very ability of being good at talking might be co-related with other base attributes.

For instance being good at talking might be co-related with tunnel vision, not having a bigger perspective, being able to connect things which shouldnt be, naivety, empathy and so on.

So if your process of conferring the title of expertise involves going through the university system, or performing well in debates or on a podium, you will get experts who are all wrong in exactly the same way and there is no one to offer them a different perspective.