"Like last year and the year before
Who remembers what it's for?"

Yes, as in: "It's just what we do", as someone else (possibly the Coppers) said of singing their old songs.

"It's just music, Brian - what human beings have always done through the generations. To pull it apart and favour one type of song over another all and call it The Tradition is divisive and inaccurate."

As I was trying to say before, 'traditional' means 'handed down', not 'one type of song'. In those endless 'what is folk?' threads we've surely established that any kind of song can be 'traditional', at least in theory. If songs of a certain era - mostly created between say 1700-ish and 1850-ish - form a large part of the traditional repertoire, that's because the conditions for active singing and generational transmission declined as mass entertainment grew in availability. As I'm about to post on your 'Steampunk' thread (I'll be brief, honest), there's a huge difference between sharing home-made music and receiving music from elsewhere.

Exhibit A was very enjoyable, but already I knew that Jane Turriff had a liking for Jimmie Rodgers (I was lucky enough to hear her, once). No reason at all she shouldn't want to sing his songs, just like Jeff Wesely fancied singing 'Ninety-Nine and Ninety' after hearing it through the folk revival. How does that affect the argument?