I feel the reason why cnn or fox have panel discusions is because they are made for tv and with for profit motive. While Npr is a nonptofit and made for radio. Radio allows npr to easily and cheaply role the news live practically 24/7 and it just opens them up to do more. While with tv news its more expensive, and they dont really have as much freedom but the auduence is larger. Tv news has to more desperately make the money back they spent.