I'm a bit confused about the timescale. Jim seems to be suggesting the rot set it when the clubs started booking professional guests. When I started visiting clubs around 1970 this was already the well-established pattern. Most people I know would say the clubs were thriving during that period and until well into the next decade, at least. So Jim must be talking about the golden era being the 60s or even earlier. If that is the case the folk scene has been in decline for 50 years or more, which I doubt most people involved in it during that time would agree with.

The clubs I see now aren't much different from back in the 70s and 80s, either in standard of performance or the material they present. As then, there is a mix of both traditional and contemporary material, and a mix of abilities. In many respects standards are higher, as more people have access to workshops and lessons. Singing from books or notes is not all that common in my experience, but neither is it a new phenomenon.