What's particularly interesting in the music sphere is that there are already well-established trends towards building a sort of ambient, atmospheric, generated soundscape. (For example, the famous "Lo-Fi girl" stream.) AI-generated content is a very natural progression here.
Regarding the broader pop music industry, a "GPT-3 for music" would likely further inequalize the relative power of labels and musicians. If people who control music distribution can easily make hit songs without needing to hire songwriters, arrangers, or performers, they surely will do so. I can imagine a lot of music-related occupations potentially having to pivot to rely much more heavily on live performances to make any money.