When you see wasted talent it's just sad. She will be managed by people a lot younger than her with less experience and qualifications. I just wish she could see she is worth more than that.
I think it's essential, particularly with the current job market, that people see their value in other terms. One of the best things my partner has ever said to me, when I was getting knock back after knock back at work, was that it was no reflection on who I am as a person.
And we all, in a sense, waste talent. If I had more time I could write more. If I'd trained I could be a good singer. If I'd focussed on it earlier I'd have been a better horse rider. If I'd studied earlier I'd have been a good musician. There are many things I could do more of and be better at, and my bet is it's the same for most people. But the key thing is, are you happy doing what you're doing? You get one life and there's no point being miserable, even if you're a CEO earning 200k a year.
Instead of bemoaning the waste of talent, I'd try to boost her self esteem, her sense of her worth as a person. It is dangerous, speaking from experience, to get that entirely from one source, especially if that source is work. Work can so easily go badly wrong through circumstances entirely out of your control, and then you're left with a fragile self worth that becomes completely broken. Encourage her to try things outside of work that are enjoyable and satisfying. Then if her self confidence improves and she wants to stretch herself at work so be it. But in the meantime, if she's happy and paying the bills, stay out of it.