That quote from Fletcher is always taken out of context. What he had in mind was that the popular ballads of his time seemed all to promote lasciviousness, drunkenness and irresponsibility - he wasn't talking about conscious political movements but change in social mores, rather like somebody 250 years later grumbling about how rock and roll led to drug abuse and teenage pregnancies.

Maybe it did. Jefferson Airplane certainly encouraged my generation to try acid and the Stone Roses must have boosted the sales of Es tenfold. Attitudinal change is just as real as a change in government.