I think her answer is appropriate. She has a staff around her who focus on all of the other details in a show. She's not going to put on a clown suit to get ratings.
While no one suggested she put on a clown suit (except for you), if she isn't focused on the ratings, it indicates a lack of willingness to make adjustments to keep the program viable. Not a surprising answer consider that the ratings she's pulling are notably less than those of her immediate predecessors and those numbers resulted in both of them no longer in the anchor chair.
An intelligent answer would have been something like:
Ratings are very important to any broadcast on a commercial network so of course I pay attention to them. While the ratings are important, I'm first and foremost focused on putting forth a quality product that both informs and entertains viewers. I believe by doing that and continually looking for ways to improve and refine the product, improved ratings would follow.