It is a great idea and all, but shouldn't we first use existing trains a lot more? There is so much untapped potential for much lower costs.

Hyperloops for passengers sound like a plan to replace domestic flights... which shouldn't exist in the first place. If you calculate in the time to get to the airport, security check, check-in, etc... it's faster to go by train in most cases, if train infrastructure became better, it would be even more in favor of rail.

So we don't have to replace domestic flights with hyperloops, just abolish them and use HSR?!

Actually I think the strength of Hyperloops could be freight transportation... iirc the Hamburg port wanted to build a prototype to ship containers from the port to outside the city very fast, which makes sense.