I'm working on AI piano lessons right now (extremely rough landing page at https://trebel.la/ while I work on the core tech). I am drooling at the idea of integrating with this thing one day...
My teacher literally would spend one hour with me on one page of sheet music to ensure I can play the notes evenly with the correct dynamics. He could hear the tiniest hesitation I have, and then come up with specific methods to help me practice that part. That is why I don't think any of such software, AI or not, actually knows how to teach piano, and I doubt they ever will.
I tend to agree with you, as I have spent many years in lessons myself and taught for a couple. But a) real lessons are expensive and difficult to access for a lot of people, and b) even for someone who has a teacher, most practice time is self-directed. I think there's a real opportunity to make practice much more efficient, and also provide a better experience than currently exists for those who can't access a human teacher.
Also, multimodal LLMs are improving so quickly that I wouldn't be that surprised if they were able to do what you're describing in a couple of years. But they are definitely not there yet.
You may want to look to Sight reading factory. They do a pretty good job allowing you to dynamically generate unlimited sheet music according to your pianistic capability.
My teacher literally would spend one hour with me on one page of sheet music to ensure I can play the notes evenly with the correct dynamics. He could hear the tiniest hesitation I have, and then come up with specific methods to help me practice that part. That is why I don't think any of such software, AI or not, actually knows how to teach piano, and I doubt they ever will.