Pseu
You are confusing 2 ideas here. Simply by using the term 'the oral tradition' does not mean we are implying that it is over a particular length of time or that it can't be broken by other forms of transmission. If I learn a song from a book and someone picks it up from me aurally and sings it themselves then that is an example of 'the oral tradition'. The only time factor involved is the time it takes for me to have passed on that song/joke/tale/proverb/piece of dialect/tune etc., aurally.