We who are alive today have very little in common with earlier practitioners of "traditional" music, and everything in common with the players and listeners of the future.

I'm not sure if that's true, in fact I'm sure it isn't. The one thing we do have in common is being alive & being human - and all that entails. Maybe people of the past were less hung up on the past than we are - in the medieval period even depictions of Biblical scenes were done so in contemporary dress, so much so that our idea of Biblical Cotume is coloured by depictions in medieval art. If people did that today there'd be an outcry!

Who taught us to look back? Maybe it was the Victorians with their psuedo Gothic and Arts & Crafts, maybe it was earlier. Maybe we've always looked back - myths, dreamings, folk tales, song lines, and just our day to day memories of those we've lost. It's a human thing, just these days our historical methods are in line with available technology.

The 1954 Definition doesn't say anything about Style or Genre; maybe that was a given in the ranks of the old IFMC, who are now the ICTM whose remit on Traditional Music is very broad. The important thing here is that wherever there are human beings, there is music, and all music is traditional. So when we die (i.e humanity) there will be no more music...