AI-generated singers routinely rank among the top-streamed country music artists in the United States -- a trend that for now is limited to a genre that industry observers fear is becoming too formulaic. Breaking Rust, Cain Walker, Aventhis, and Outlaw Gospel have more in common that cowboy hats, denim and leather. They are all completely computer-generated, from their faces to their melodies. And they are all hitmakers. "That's a phenomenon I didn't see coming," said Jennie Hayes Kurtz of the country music band Brother and The Hayes. "I thought AI was going to be curing cancer or something." Many of...