most of the moaners do not actually play or perform themselves

Sweeping and contradictory.

There are those who certainly play competently though not in public performance because they do not feel they are adequately rehearsed, or have sufficiently honed performance skills.

Which has precious little to do with "unaccompanied trad groups" which the OP somewhat improbably believes to be thin on the ground when actually you can't step without falling over them.