The U.S. which is reputed to be one of the "freest countries in the world" has the most restrictive policy in TV transmission in the world. Occasionally, NPR will run a special on "The Carter Family" or "The Grand Ol' Opry" but because of the associative connotations of folk music with "leftist" or "radical", the media won't touch it because of the sponsorship concerns.
Also, what sells in the US is more important to the broadcasters than is what's good for the public. That's why US TV is the biggest purveyor of crap in the world.
Another problem for the broadcasters who are not in the business of educating the public but pandering to their lowest tastes is that Folk is fairly esoteric these days. We can't define it here on this chatsite so how can it be marketed successfully by neophytes?
I've heard people in the Bluegrass community speak of folk music as if it were something different than what they listen to as well as blues officianados. Folk has come to mean a sterotypical image of a scraggly-looking person playing a guitar in a coffee-house. When Joan Baez removed her shoes in concert, she was followed by a succession of barefoot contessas.
TV or not TV, that is the question. Is it nobler in mind to suffer the slings and arrows of outrageous programming or take arms against a sea of garbage and by so opposing it, at least get rid of American Idiot Idol.