SpaceX received uncounted billions' of dollars worth of R&D for free thanks to the existence of government-funded space programs, which already solved many of the difficult fundamental problems in the field of rocketry so SpaceX wouldn't have to. And while it's neat to watch the stuff they do, there's very little SpaceX is doing that's revolutionary as opposed to evolutionary. So of course now SpaceX can come in and reduce the costs by building on the existing base of work in the field.
Hyperloop doesn't have anywhere near that amount of free R&D or established, easy-to-increment-to-get-there technologies to draw on.
I wouldn't be so sure on that. The R&D transfer and ready human capital was definitely profound in SpaceX's case, but if it was that incremental, why didn't NASA or anybody else do it before?
I think almost the sae can be said for Hyperloop. There's no fundamentally new technology that needs to be engineered for it to work. Maglevs are common in many countries, evacuated tubs aren't complicated.
All that said, the US seems to be the wrong place to start Hyperloop. Regulation and land property will most likely be the biggest hurdle, not technology, especially in California. Hyperloop seems to me like a perfect project in China though, in regard to property rights, regulation, city planning, human capital in the high speed train sector, as well as crazy supply side economics.
Why haven't we gone to the moon since the 1970s? Because there wasn't the political will to keep funding the programs that went there. Why was the Space Shuttle such an awkward and ultimately non-viable way to go to space? Because there wasn't the political will to fund genuine reusable launch technology. SpaceX's big advantages are in having the hard up-front R&D already done for it by someone else, and in not having to rely solely on political decisions for the existence of its market; even if there are no more nice-PR resupply missions to the ISS, there are still going to be private actors who want to launch satellites.
You're moving the goalposts. The argument isn't that evacuated tubes are "complicated". The issue is that the cost estimates Musk provided appear to assume secret Musk space alien technology.
Hyperloop doesn't have anywhere near that amount of free R&D or established, easy-to-increment-to-get-there technologies to draw on.