I see it like this:

Our legal system has the concept of mechanical licensing. If your song exists, someone can demand the right to cover it and the law will favor them. The result of an LLM has less to do with your art that a cover of your song does.

There are plenty of cases of a cover eclipsing the original version of a song in popularity and yet I have never met a single person argue that we should get rid of the right to cover a song.