1. The teacher is not a good fit if expectations are mismatched like this. You could talk to her and explain that she must expect less of this student. Often teachers have one or two stellar students that are on competition tracks, and a majority of others who are on less demanding tracks. However, you need to ask yourself whether this is really the right teacher for your child, because it seems as though this teacher is not teaching your child how to practice efficiently.
2. Which leads me to the most important aspect of any activity - learning how to learn. Meaning, efficient practicing so that progress is made in as short a time as possible. Scales and arpeggios to tune the ear daily, then etudes to practice specific techniques, then the show piece, in short fragments. What matters in all this is for the student to LISTEN to themselves, and notice intonation, rhythm or phrasing issues. It's the hardest part of music training, knowing how to listen. Once you know where the problems are, the job's practically done: you can solve some problems with different fingerings, or bowings, or if it's just a question of muscle memory, practice very slowly, or if it's a tricky rhythm, practice with several different rhythms, etc...
3. So perhaps look for a smarter teacher