Black Walnut - Arnie who? I assume the festivals you are mentioning are in the U.K.?

Over the years I've seen trends shifting at various festivals here in the northeast U.S.   While singer-songwriters have become the overwhelming favorite, there are still spectacular festivals that find room for both.   Old Songs is probably a good example. The New Bedford Summerfest has done some wonderful scheduling.   Seeing the Copper Family share workshops with singer-songwriters really helped show the connection.

Here in the U.S., I think the majority of attendees go for the ambiance and good time. Hardcore folkies and hardcore singer-songwriter fans make up just a small part of the attendees. Festivals that cater to families, provide a diversity of entertainment, good food and most importantly - good value - will do well.