Too mucch of a simplification Jed
As Dick |Miles has pointed out, a football crowd can improvise a verse or a rhyme which is then passed on orally - the same with crowds of children in a schoolyard - all orally transmitting (and creating)
Shantymen orally created on the spot to get a job of work done.
We have two examples of groups of men (in rural Ireland and in the travelling community) who composed on the spot by throwing verses at each other until they arrived at substantial songs.
I'm in the process of preparing a talk on collecting which, part of which, I believe, shows what happened to the oral tradition among Travellers when their tradition came to a screeching halt in the mid 1970s
We started recording Irish Travellers in London in Summer, 1973 - we got so much information that we had to call a halt and form a plan of work - we didn't restart until 18 monthes later

" In 1973, we would turn up at a site, find a singer, record him/her for as long as it was comfortable, then adjourn to the pub with them and chat, hopefully gathering information that would enable us to pick up next time.
Occasionally, when we were thrown out of the pub at closing time, we would return to the site to find a fire had been lit and the families had gathered around to chat, tell stories and, on several occasions, sing ? when this happened, we were invariably invited to join them and, if we were really lucky, to record.
When we turned up on spec on Easter Sunday, 1975, we were greeted with an empty site, not a soul to be seen, all doors closed and strange flickering lights in all the windows ? ?progress? in the form of portable televisions, had arrived with a vengeance and the song and storytelling traditions had fled ? virtually within eighteen months.
We had to sit through the western. Rio Bravo (for the umpteenth time) before we could tempt somebody to sing into the mike for us.
Jim Carroll