It's the principles that have enduring value, if not the outer expression of form and technique. Unless the applications are refreshed and adapted to be relevant to contemporary combative situations and needs, koryu will just be living "museum pieces," frozen and preserved in time to show how things were, in their day. There's a lot of stuff in koryu that is not particularly pragmatic in real times. I love a good koryu (Kukishin Ryu and Takagi Ryu, for example, still rock, in terms of their potentials), but they have to be adjusted to being practical in contemporary application and not just practiced ritualistically.
But at least koryu work on an actual methodology. The performer in the kata demo presented in this thread, has no background in any established sword system; it's just choreographed martial-ish dance. She admits in an interview that her coach likewise has no sword training, and made up the moves for her routine. No harm, no foul, as it's meant to be performance art that has a martial "feel," but they are not making claims about its efficacy or provinence.