Results of my Google searches.

UK folk festivals 2017 - About 31,000,000 results (0.67 seconds)
UK folk festivals 2007 - About 14,100,000 results (0.71 seconds)
UK folk festivals 1997 - About 7,200,000 results (0.75 seconds)

As I said earlier, unscientific.

But it matters not as we have already shown that on the database of http://ukfolkfestivals.co.uk there are 100 more festivals in England today than there was in 2010. A bit different to your bold statement that Folk Festivals are disappearing. If you can find something factual to back up that the general trend is a reduction in the number of Folk Festivals I am willing to listen.