[snogglethorpe]

Even standard HSR is a lot more complicated that that—you can't just put a bigger motor in a slow-speed train—but it certainly benefited from the large amount of commonality with lower-speed rail, and most of the higher-speed technology was developed over time, with real testing. [Note the first Shinkansen was a fair bit slower (~200km/h) than today's highest-speed models, and ramping up the speed from there occurred over many years.]

Japan is also building a real (long-distance, high-speed) maglev system. It's much more of a leap from standard rail than HSR was, but again, they're using technology which they actually have long-term real-world experience with.

Hyperloop, by contrast, doesn't even have a lab model. It's a diagram on a napkin, with some of the calculations worked out.

The press and the general public may not notice this distinction, but people investing large amounts of money most certainly will...

[tehwalrus]

I think the point is that a "lab model" would be useless, since the problems change non-linearly at scale and speed... and computer simulations of fluid dynamics and physical systems are pretty good these days, since computers got so much faster (physicists add more and more complexity/realism to their modelling such that a simulation always takes ~3 days to run, however good their computer. Our computers are awesome now.)

Also, some parts of it are tested, e.g. the roller coaster magnetic thrusters/brakes.

I do understand the difference, but the point stands for all revolutionary, as opposed to incremental, technologies. We will need some, how do we fund them?