Why? People don't switch now for the sports? Why would they switch for the arts?
Because people want sports, that's why the news shows it. If the arts were merely foisted on viewers without demand for it, people wouldn't bother watching.
There are now about 8 channels that are 24-7 sports that are included with the most basic package on Direct TV. There are none included that are 24-7 about current happenings in the Arts. That is not some top-down decision made by anti-art execs. Its a response to public interest. Any art channel that was popular would be about the mind mundane, souless, non-intellectual, a-political art out there, because that is the kind that would serve as a form of mindless distraction most people seek from their t.v. viewing.
The news does impact society, even if mostly by reinforcing and satisfying our desire for particular kinds of information. If something isn't in demand, then it can only be included and have an impact, if its "snuck" into the news at random points, where most viewers would just sit through it and what for the coverage they want to return.