The Signalling Benefit of a College Degree

The signalling model of education says that getting into a college indicates two employers, to other people, that you have these innate abilities. And maybe the school does nothing to change your abilities, but the very fact that you were able to get into that school tells employers something valuable That makes them willing to pay more for you. But why? Why would anybody consider those as necessarily mutually exclusive? I pates as a minute. It seems, oh, they're pretty clear to me. They're not mutually grated.