I wouldn't say her PhD is in the field she sucks at. It's in a very close adjacent field. That's often when PhDs make these huge public mistakes because it's not their expertise, but the feel like they've learned a lot just from how often it's come up, and then they publicly display that they way overestimated themselves.

I agree she sucked and that it's time for her moment to pass. I just don't like this being used as an example of why you shouldn't listen to experts. You generally should listen to them, but only about their area of expertise. They'll like to get real confident about other stuff sometimes, but this is when you ignore them.