Well, as I said above , I think the reason people balk at the word "museum" in the ballet context is that we recognize that in order for dance to come alive, it has to be of this moment. The notion of an old ballet painstakingly reconstructed suggests, at least at first blush, a dinosaur put together bone by bone — the closest we'll ever get to see one, but definitely dead.
Of course, it doesn't have to be that way at all; good ballet masters can make an old ballet come alive for the dancers and through them, the audience. But in answer to Bobbi's question, I think that people jump to the first conclusion.