It's easy to say that Zucker should suck it up, practice more, and be more motivated, but at a certain point, pain becomes overwhelming and takes over concentration. It's clear her coach doesn't believe that she's crossed the line between the chronic pain that athletes (and dancers) live with all the time and the debilitating kind.
It's one thing for a coach to have a single way to approach his students -- for example, he speaks of cooperation and then complains that for Zucker, that doesn't mean she is on his team, but that he is on hers -- or not know how to train injured athletes. Then it's purely a matter of incapatibility. I thought it was very descriptive moment on film when after he asks her to stay for her LP score at Regionals, when she is ready to leave before hearing that she has no chance for a top 4 finish, she heads in one direction, and he in another. But the self-satisfied little smirk of schadenfreude that he gets when describing her failure needs to be slapped off of his face. If I had a child in skating, I wouldn't let my kid near him.
In the last episode, where she finishes in 10th at Regionals, she has made the mental connection between being physically unprepared to compete and lack of practice. Whether she accepts what this means for her future is yet to be seen. But she's a kid who had enormous success until this past year, winning the Junior National title, has a father who is a former professional athlete, and has a family who continues to sacrifice for her. Given her father's description of how he and her mother have done everything for her -- as he cleans her kitchen -- and paid for everything, what other identity does she have? I certainly would be in denial in that situation.