The monkeys for the hyperloop to be viable were things like whether you could safely load and unload passengers or cargo, and whether you could get the system up to speed and get it to brake without incident. A couple hundred yards of track wouldn’t tell you anything about whether you could conquer those challenges. In fact, Teller and the team at X figured out that you would have to build practically the whole thing before you knew whether it worked. You would have to build a bunch of pedestals before you could find out if the monkeys were intractable. They quickly decided not to pursue it. One of Teller’s valuable insights is that pedestal-building creates the illusion of progress rather than actual progress itself.
Annie Duke in Quit