It seems a touch, what shall we say, fundamentalist, doesn't it? If JK wants to return to some (hypothesised) traditional way of dancing, the first thing he needs to eliminate is the caller. people just knew the dances- and it could well be that "the" tune as noted in old tune collections acted as a reminder to the dancers of what they were supposed to be doing- in other words, the basket always happens on the third part of Green Gangrene, or whatever. Or that they started with that tune, and once everybody was into the swing of things, started on the variations (of the tune, or brought in a new one). In the absence of contemporary recordings, it's difficult to tell.

It's also notable that many tunes in old collections are not explicitly associated with any particular dance, so we have to hypothesise that everyone knew which dance they belonged to, or that they weren't played for dancing- or that they floated.

Much as we all respect JK, I have to agree with him- it's cosmic claptrap.