What does “rarely get to write songs” mean? Is there a powerful Committee of Songwriting who determines who gets to write the pop songs? I think a better way

What does “rarely get to write songs” mean? Is there a powerful Committee of Songwriting who determines who gets to write the pop songs? I think a better way to look at it would be to address how song writing credits are assigned, who is getting them and why? Are male producers and session guys, forcing their way into the credits or are artists sampled or with similar previous work being preemptively added?