She got more confidence and experience. That makes her a better leader in her next job. She moved on and chances are that she got a better job because she could convince somebody that she can succeed in a difficult environment.

Quoting parent: "Sadly, she eventually got beat down enough arguing with management to leave"

That is not more confidence. And likely, she does not want "difficult environment" job either - could have stayed for that. What you learn in such environment is to spot red flags sooner.

Such positions are not rewarded, she did not enjoyed that, she will likely seek different position next.