The Beatles could not get a deal till Brian Epstein effectively paid for one. We all know the stories but who deserves the credit for success? It took one person’s unshakable belief. It took one person to believe in others when no-one else would. The true star, in this case, is the agent.
What about JK Rowling I hear you say. She was turned down by 9 publishers and she’s an artist? But in this scenario she is a Manager. So yes, as a Manager, she deserves credit too !