There's a fairly sizable difference in agility between a small web startup and a massive, political infrastructure projects. Approaching the latter as if the lessons learned from the former can be naïvely applied is, well, naïve. Move fast break things is cool and all when the stakes are low; when the stakes are high it is irresponsible at best.
EDIT: Also, a Hyperloop that terminated where the PDF proposes just wouldn't -- and probably shouldn't -- get built.
"Also, a Hyperloop that terminated where the PDF proposes just wouldn't -- and probably shouldn't -- get built."
I'm sure we'll see it in built in China in a few years time then. No doubt it will be plagued with problems, maybe a few deaths. It'll be labeled a white elephant for a few years. But in 25 years time when everyone in China is zipping about at over 1000km/h and people in SF and stuck in traffic shouting about the good old days and refusing to build anything new because good isn't perfect, you'll be lamenting the lack.
I know it's sometimes easy to forget, but technology is not now and has not ever been destiny. Certainly a better people mover will get built, because it's a problem that isn't anywhere near a local maximum. Maybe something like the Hyperloop will be the solution to some small subset of the people moving problem. Maybe the Chinese will take this baton and run with it.
But I doubt it. And in any event, the idea that we should build a toy project because it offers some improvements to some parts of a current problem for some small number of people is a perfectly defensible one -- on Hacker News. As an actual spending cash sort of idea, it's fairy tale nonsense. You can see how seriously Musk takes it by how serious the proposal actually is w/r/t nuts and bolts -- not at all.
EDIT: Also, a Hyperloop that terminated where the PDF proposes just wouldn't -- and probably shouldn't -- get built.