Potentially controversial opinion: nothing really changes for musicians / artists. There already is an abundance of fantastic (human-made) music for every genre or taste, even before AI arrived.

Artists' biggest challenges today aren't related to making music. They're related to marketing, building networks, building their brand, touring and physically playing shows, getting eyeballs on social media. For every artist that "makes it" there are 100s with equally good skills / product who don't b/c they fall short in any of the above.

So when AI lowers the entry barrier to allow millions to make music that before were limited by their skills, that's great! However those millions of people were never capable or even interested in marketing or selling their art in the first place, so the market competition to serious artists is quite limited.

TLDR: Music is and will be an overcrowded marketplace where brand matters a lot more than skill. AI helps with the skill but not with the brand.