Why do people like to watch shows about SINGING?

I watch America's Got Talent because it's the same appeal to me as watching someone singing on the streets, someone performing illusions and magic on the street, a group doing acrobatics on the street.

I wouldn't just walk past something like that, and these shows know the same.
I don't watch American Idol unless they have a Beatles episode which a lot of the time for some reason, they do. The appeal to me is just that I like hearing people sing, and sing good, and a lot of the time that happens on American Idol.