I am not sure about these statements about standards of performance being higher in the 1960s that they are now. In general, the younger generation of performers have blown away previous ones in terms of their musical instrumental standards. There are plenty of bad singers around now - but then there were plenty of bad singers in the 1960s.
What these earlier times did have was a sense of excitement, of innovation, of purpose that the scene has lost as it has matured. It has also lost that naivety that was part of its charm.