I should call that 'a development' or an 'evolution' rather than a revival: the 50s onwards revival hadn't gone away but was simultaneously ongoing, and these things were just different manifestations of it, different forms it took. There was nothing to 'revive' because nothing had died, in the way that the impetus initiated by Sharp et al had died away during the 30s-40s. The well-known history of the Copper Family being REdiscovered by BBC Home Service's Country Magazine is instructive here.