I think this is really it. Being a musician was never a very reliable way to earn a living, but it was a passion. A genuine expression of talent and feeling through the instrument. And if you were good enough you could pay the bills doing work work for studios, commercials, movies, theater. If you were really good you could perform as a headliner.

Now, AI can generate any kind of music anyone wants, eliminating almost all the anonymous studio, commercial, and soundtrack work. If you're really good you can still perform as a headliner, but (this is a guess) 80% of the work for musicians is just gone.