My experience of folk and folk clubs started in the late 60's.
At the start there was one club in Plymouth, after a personality clash a second club opened to cater for sympathisers of the alternative side.
In the years following that it progressed to a club on every night of the week.
None of the clubs had a strict one sort of folk policy,a bias yes, but all were tolerant of other sorts of folk.
The attendees were largly late teen early twenties, and single.
Many of them subsequently married and became parents,the raising of their offspring stopped their attendance at the clubs,the youngsters who followed had different interests and didn't come to clubs and so the numbers of clubs declined.
Jim may have lost his interest in clubs because he couldn't find the
things which interested him,to say that was the main reason for the decline is a generalisation.
The world moved on for many reasons,the paradise you remember in the past was hell for others.