Jim, thank you for your thoughtful post.
In the US there are also many tunes that are unattributable or anonymous. There is a tradition to back them up. With this caveat, there is also a tradition of songwriting that comes out of jazz, pop and other composite forms of music that is not just for making money but is an art-form.
Sometimes there are examples of anonymous songs which have a popular song base because at one time they were associated with musical shows such as Dan Emmett's
"Old Dan Tucker" or Stephen Foster's "Angelina Baker" which became "Angeline the Baker".
if what you say is true, what makes a song traditional is its acceptance by a community than it has to be argued that the American popular swing songs are a form of "tradition" as well. (Not to ignore Rock) Many of what makes for Folk Music came out of performances by songwriters attempting to pass the hat in one way or another. "You'll Never Walk Alone" I assume is the song featured by Rodgers and Hammerstein in "Carousel". It can be argued that their creation of the song reflects some kind of tradition as well and not just a desire to make a buck. It must be stated that in order for a song to acheive success on the Broadway stage, it will have to have been altered and rewritten and re-performed many times before it is "frozen". Then often it is accepted by the "community" of people who attend the show and incorporate it into their own experience and recreate it once again. I can assure you that there is nothing crude about "You'll Never Walk Alone" compared to much of the folk song doggerel that is passed off as traditional.
Ireland is a different place than the US and the idea of fostering the music of the Nation has to have a self-conscious aspect to it but this doesn't in any way denegrate the important work of the CCE. Irish music is beautiful and I am an ardent fan although I'm sure there are academics who would take exception to my being enamored of the "Celtic Woman" and the "Clancys and Tommy Makem". In this way I see Irish music as I do American, that which takes root because individual performers bring it to life in their own way. Needless to say, Tommy Peoples is probably not accepted by the CCE, but he is a fine example of a great interpreter of Donegal fiddling.
The problem with Traditional music is that it needs to be interpreted and received by a public that appreciates what the individual performer does with it. I would have to disagree with the notion that only the "oral tradition smoothes out individual composition because I believe that each song sung is changed by the person who sings it regardless of who wrote it and therefore a smoothing process has taken place. When you look for the anonymous songs, generally, there is a starting point by a composer. Maud Irving's "I'll Twine Midst the Ringlets" becomes "Wildwood Flower" by A.P. Carter's delightful tinkering and the smoothing process that makes the song the unofficial anthem of the rural South US is attributable to the Carter Family's re-interpretation.
Is not Sean-Nos an unaccompanied tradition?
i think in the case of any better songwriter, the narrative of the song becomes important.
Narration however is not always tied in with the utility of every song.
it might be that the idea of "tradition" is a slippery slope because it continually needs to be redefined. Even in an old variant of a song, poly-traditions seem to play a role. When we speak of Irish music, of which tradition do we refer? Certainly not some fog-laden mystic Celtic Druidism but the influences of European, Spanish, and American early pop music are inherent there. Even Middle-Eastern if we are to believe what some musicologists have said.
i am thankful for a David Downes or a Bill Whelan who takes and reinterprets the music that they hear around them and if some want to call that "trad" that's OK by me. But I don't see much difference between that and what some academics call "trad" which contain various musical influences that constitute a style.
I see "traditional" as a word bandied about by academics who want to rarify their musical tastes without exploring the nature of works that fall outside of their purview.