Hyperloop would have been built on pylons, theoretically mitigating the impact of a line cutting across farms or cities, which in the case of CAHSR has caused i

Hyperloop would have been built on pylons, theoretically mitigating the impact of a line cutting across farms or cities, which in the case of CAHSR has caused immeasurable political problems. I suspect the actual technology within the tube was never Musk's initial concern. Similar to his other industrial endeavors, I think the calculus with Hyperloop had more to do with the economics of being able to manufacture pylons and tube segments offsite for quick assembly onsite, leveraging factory production and avoiding as much as possible site-specific costs such as land grading. And presumably he had in mind repurposing SpaceX technology for welding rocket bodies. Given a cost-effective way to build and put these tubes into place, and some ballpark figures on their characteristics--e.g. how much of a pressure difference they could reliably keep without inflating production costs--figuring out how to actually use them was just an engineering problem, which he then took a first crack at to satisfy himself the overall concept might be feasible.