I don't know how I can add anything to this, as we now have a cyclical argument going on, But I want to say that I like Superman not being the first.
I think the point being missed is that Superman wasn't inspired to be a hero by the GA guys. He was a hero on his own. That they inspired everyone but the alien is cool to me. Who are the main aliens in the DCU? Superman and the Martian Manhunter. They weren't inspired by the Golden Age heroes. They were inspired by a desire to help and a desire to be a more effective - more far-reaching - detective, respectively.
I love when I see the old JSA guys give Superman encouragement or advice. I like there being someone for him to go to, other than Batman, when he needs help. In fact, I geek out a bit when Jay or Alan call him "Clark."