This was all addressed in Protagoras's comment and my reply. Please recall that I was responding to a comment proposing that "that some cheaper/better alternative that we're not considering [might be] developed before anyone gets around to building the hyperloop"; I am not the one who is defining the scale of innovation necessary. Obviously, "driving a car with CVT" is not an alternative to "driving a car," and helicopters are not a generally better transportation technology than cars/trains/plane. (It's better in a few specific situations, but obviously for the ancestor's claim that a "better alternative" would be sufficient to prevent a hyperloop from being built, better needs to be interpreted broadly, in the sense that cars are better than a horse and buggy.) I feel like it's pretty reasonable for me to have assumed that readers would have read the comment I was replying to.