I don’t really disagree with your points. But I went to school for performance and composition knowing full well the degree wasn’t needed, but the education and networking available at a top school at that time had value. I have zero regrets going to school and then leaving before graduation when opportunities to gig were enough to justify not taking on more debt. I gigged for fifteen years (before burning out and rebooting life like a total cliche) and in all that time I was still getting work through connections I made from school.
I wouldn’t recommend to anyone that they must or must not get a performance degree, just that they understand what their goals are and how much school overlaps with them. A worthless degree doesn’t mean the experience isn’t worthless to build a career. Working freelance musicians absolutely exist, it’s an achievable career, and most I knew went to school.
Personally, I never liked the idea that teaching as a fallback career because I think students should be taught by people who want to teach first and foremost. Burnout mediocre teachers can be woefully uninspiring.