There's literally no detail to any of the logic or rationale in this story. People like faffing about these fantasies, but the most important advice I've ever received in my career was from my father - "Don't quit your day job."
You have one life to live and if you don't love what you're doing (she doesn't) and has the skills to do something else (she probably does) and has the guts to change her situation (she does), then in my opinion, she is making the smart and responsible decision.
She did, I can, so can you. Yeah best to have some savings or you may be homeless and hungry for a while but you absolufreakinglutely can, and should, quit your job if it makes you miserable.