You're not addressing a key part of the problem. I studied with a major US orchestra, so I'd like to think I know something about it. It's arrogance. It's that classical music is better than other music genres. There are younger "orchestral" composers out there who want to write music that a younger audience likes, but they struggle because it's beneath orchestras to play it. There are some age biases, I will give you that. And of course demographics dictates the money orchestras make, which determines what's played, and orchestras don't want to upset the money flow. But maybe try! Try something new that's marketed to a younger audience. It's just like cars. Cadillac has a reputation as an old person's car; and they've had a very hard time trying to shake it off—but they are trying with certain models. Really, it's the same situation with orchestras, so try!