Get in line… lots of people think I’m wrong.
I’d suggest that the mediasphere is no longer stable, and that different people get their news in vastly different places. There is no one “authoritative news source” any longer, I’d argue. The whole “internet bubble” (which is probably stronger on places like FB, but IDK, as I’m not on FB) only serves to reinforce our own world views, even those views that understand how we get our news. So, maybe it’s more like FB is the primary news source for many people, but that’s only going to further mediate people’s access to news, it’s yet another layer of fragmentation. So maybe (if you’re on FB, you might not be) you’re feed has plenty of CNN stories, but that might not be true for everyone.