PRS Member,
Your point might have been better made if it hadn't come with the baggage of such phrases as (can't remember exactly) "leftie academics looking for a gig" and "romantics". Your current one of "some collector wandered in (to a pub) with a tape machine or a notebook" doesn't help much either. I don't know anybody who "collects" or has ever "collected" like that; to my mind it shows a great misunderstanding of how people like Sharp, Vaughan-Williams Grainger, Kidson, Broadwood, Hamish Henderson, Tom Munnelly, Mike Yates, Alan Lomax, Hugh Shields, Seamus Ennis et al worked. Sure, musicians or singers looking for tunes or songs to play or sing might sit in on a session with a recorder but that isn't collecting.
You wrote:
"The artform is nebulous except in one respect - that, like all art, it belongs to its maker and no-one else."
By and large, one thing that distinguishes traditional songs is that they are anonymous; (like most of the other characteristics applied to the tradition, there are exceptions, but it works for me as a general rule). As has been pointed out earlier in this thread (notably by Anahata), it isn't how the songs started life, but what happened to them as they were passed on from mouth to mouth and from group to group; this is what makes them traditional. You pass rather lightly over registering the arrangements of songs "because they let me". Basically all traditional songs are arrangements and by claiming ownership on behalf of an individual or company, you are effectively killing off their traditional nature. One of the overriding impressions I have been left with in my contact with traditional singers and storytellers has been their stunning generosity in passing on what they have. This, by the way, has also been the case with "leftie academics" (with a few notable exceptions – usually not lefties) who have been more than happy to pass on the results of their work and their ideas to others. I have always been lucky enough to encounter people who are involved in the music because of their love for it and not for any commercial or prestigious potential.   
You went on:
"If songs are well-written in the first place……………… they'll stand less chance of being changed over time".
Songs were changed for many reasons: adaptation into new situations, times and circumstances, disuse, poor memory not backed up with literacy, simple accident of the collector being in the right place at the right time… many, many more reasons. Survival is by no means a yardstick for quality.
You also wrote:
"The tradition is a poor term for such riches".
I can't really agree with that. It works for me as an indication of how the songs have been made, received, re-made, adapted and passed on. It is a term that traditional singers I have met have been comfortable with and have used as a way of acknowledging the debt owed to the people who passed on the songs to them.
Bob Coltman;
Thank you for such a thoughtful contribution to the discussion. Had past debates on the subject taken place with such thoughtfulness, without we various schools of thought crouching behind our respective barricades and hurling invective, I'm sure we would have moved on much further in our search for an agreement on definition.
Most of what you write I have no great argument with, apart from the occasional quibble.
I don't accept the idea tradition is in the ear of the beholder any more than I believe that the same can be said of classical music, jazz, hip-hop, reggae or any other musical form. If it were the case there would be little point of us discussing it as we would have no reference point of communication. In my experience, the same was not true of traditional singers, at least, not the ones I've questions.
I really don't want to re-argue my case, but if anybody is in the slightest bit interested they can hear what I, and some traditional singers have to say in the Enthusiasms section of the Musical Traditions web-site under the title 'A Folksong By Any Other Name'.
My main opposition of the present argument lies in the question 'where do we go from here?', or 'what future, if any, does traditional music have?'
None of the possible candidates you gave for future traditional songs fitted my bill for one reason. For me, one of the distinguishing features of English language traditional song is its narrative quality, the singers being storytellers whose stories come equipped with tunes. In the past these stories, as well as being entertaining, have carried the history, aspirations, experiences, emotions, values, etc. of the communities they served. I would argue that we no longer communicate in this way – I have written elsewhere in this thread of my belief that we have now more-or-less become passive recipients of our culture rather than participants. I would very much like to be proven wrong on this point.
Jim Carroll