Steve - the main causes of the decline of the scene are both obvious and were predicted - what happened later may have had numerous reasons
Standards were bad and getting worse and people were turning up at folk clubs and not heaing folk-songs
What remained has proven to be non-sustainable
That makes total senswe to me
If I want to hear Ed Shaeran songs I go to the master, not the sweeper-up
If I want to take pot luck there are other, better organised laces for that

I think it's common sense to think that the more you learn of the song the more you are likely to want to sing or listen to it again
Research and performance have always seemed inseparable to me
Now we have the internet and forums like this we are able to add constantly to both our knowledge and enjoyment of the songs - it would be a crying shame to waste that
I have recently added around a dozen 'must-learns' to my list from my Irish Child ballad work
Jim