Another reason for the decline is ossification. A lot of sessions have had the same core of regulars for many years, and they evolve a conservative culture where a newcomer is discouraged from bringing in any new material. They'll either meet with "we used to play that but we got bored with it" or "we don't already know it so we're not going to try".

Some sessions have setlists. These are an unmitigated disaster.

A lot of us got involved in Scottish traditional music because of its limitless variety and unpredictability; there's far more in it than anyone could experience and learn in a lifetime. You'd never guess that from watching a roomful of old people playing the same repertoire every week off a table covered with paper.

Not all sessions are like that, but far too many are.