That is the most “glass half empty” post I’ve ever read. Sigh. I’m sorry. Your suggestions are good, but she does not want to see it. I guess I’d lay out what you will and won’t do financially, what your expectations are for ongoing communications with her, and let her know she has the option of a gap semester (if she can keep her scholarship).
Lots of people keep music as a hobby. They play in community bands or orchestras, play in the pit for local musical theater groups, etc. It is an option, at least.
I would provide her some stats on the financial benefits of a four year degree. Can you get her to spend some time in the career services office? She can tell them she is having trouble picking a major – they may be able to help, and they aren’t “mom & dad”.