I talk from my experience and i visit the uk more frequently than you, the crib sheets occur much more frequently in non guest folk clubs singaround type clubs, there are fewer guest booking clubs so the standard has dropped partly because of that, however in the guest booking clubs the standard [in my experience] is as high.
the availabilty of venues is another problem the singing of buddy holly songs was started by a perfprmer called AndyCaven, in 1980, 38 years ago.
the club he is resident of, Colchester, do book trad artists but ,i think your crticism although over exaggerrated has some basis in truth. I know that I do not want to go and listen to an evening of buddy holly songs