I’m not a music lover,but if I am it is because I like but music and not the artist. Whoever sings it does not matter in the sense that it doesn’t have to be an A-lister, as long as the music and lyrics are great. However, an A-lister is chosen because of his or her reputation, and the composer believes that an A-lister has a greater chance of popularizing the song.
Having said that, some risks are worth taking. Remember authors of Harry Potter and Lord of the Ring!
There are talents to be discovered, that are outside of the box!