They don't "fail", they end. So does everything else. Every human life ends at some point. Every plant ends. Every season ends. Every form of government ends. It's not failure, it's just the end of that particular phenomenon, that's all.

The main reason you see folk music radio programs ending lately is this: a dwindling demographic to support those programs, and less money to be made in that field, as compared to other styles of more commercial music that are presently being pushed by the mass media and the major marketers. That's normal. It has happened the same way with horsedrawn carriages and flintlock rifles, for example....but...you can still find some horsedrawn carriages and flintlock rifles if you go to the right places, and you will probably always be able to find some folk music too.