I don't think folk music will fade. It reached its peak in the 60's when someone gave a 50's beatnik a guitar, but even then it wasn't mainstream. It was just a new form of music that drew an audience. It will always be that, really.
I also think that folk music will not fade. Even now I can see that it is popular among my children's friends to play bass guitar, piano and even violin. I heard that playing and listening to classical music helps developing brain (sharing an interesting source ), so I think it will stay with us no matter what. I am glad that my son recently has started playing the bass guitar (recommend this one). We are more than satisfied with the sound. Now we have even more atmospheric evenings among family.