I don't know enough to form an opinion on whether she's being truthful or not, but it's not at all hard to understand why there aren't more cases. If she's telling the truth, then losing your career is the price of coming forward. Not only at Fox News but she might very well have a problem at other outlets. So it's rational to conclude others might have put up with it as the price of keeping their jobs, or even encouraged it as a way to advance their careers. We just don't know.
My wife went through something like this and I can attest that it's very traumatic, and deciding what to do is difficult. She essentially had to decide if the very real possibility of losing her job with this entity was worth making a formal complaint, when like here there was no sexual assault, and everything said was between the man and her, with no way to prove her case. Eventually she shared her story with the female (and that was significant) person in that division who was the reporting person for these kinds of allegations. Originally the issue was "solved" by separating them, and only when that didn't work did she move up the chain, and file a complaint. Luckily, that entity had a serious policy against sexual harassment, perhaps because the majority of their hires in a technical field were women, and things were resolved to her satisfaction. It helped that during the investigation others confirmed the basic story of this guy's behavior with women when given the chance to do so anonymously. But when making the leap, against a person FAR superior in rank, it's a helluva risky leap, and a difficult choice - your career in a he said/she said case. It's obviously FAR more risky and difficult when the person you're accusing is THE boss.