Being a middle-age amateur with tough working schedules, I thought to offer a different perspectives.
She is hard working, musical and committed to improve. I don't wNt her to become stale and lose her obvious passion.
Passion may come from inside, then, you may not have to worry about it. Did she express to you that she really wants to be a performing musician? Is her motivation coming from the idea of performing for audience? Or is she simply wanting to enjoy music on her own and with friends and family?
While I am not at a performance level at all (I play advanced repertoires like a dead wood), it's funny I do get asked to perform from people who somehow think I am good enough (e.g. neighboring church...). But I never want to perform, because I can never predict my business schedules. It'd add so much stress to think about performing when I may get a huge business project. I do enjoy playing 4 hands with friends or play accompaniments for my husband (tenor) to practice. But ultimately, I just practice as much as I can accommodate even if no one hears me. Since my teacher thinks I am not a performance material, it actually works. I think I will flip out if my teacher puts me to perform. At this moment, I am so motivated to get many Scriabin in my hands, I don't need any other motivator.
So you may want to ask her what are her near term goals and how they fit in her life. She may just keep going without any external outlet.