Is there not also a tradition of a fair few of our traditional English songs being associated with licensed begging? (in other words, performing for money, food and beer - especially beer). See Ronald Hutton, "Stations of the Sun" for more details. In fact see it anyway - it's a very good read and he's a great proponent of evidence-base history. Of course people have always sung for pleasure - unmitigated by commerce and money - and especially in pre-radio and record player days. But to claim that that was the be-all and end all sounds like taking a present day argument within folk music and trying to force an historic precedent on it.
Meanwhile, I'm rather enjoying Alison Krauss and Percy on Later.