Vacuum maglev pipes require cooperation from the people whose land you’re going to take via eminent domain.
Do you think that kills the idea? We have two major cities with 300km of mostly farmland in between where I live, so I'm pretty sure it would be no problem here - if investors would fund it.
NIMBYs are always a thing, but based on my local knowledge, I think a deal could be arrived at. There's enough room nobody would lose their house, and most of the land is owned by big farmers that see it as no more than a number on their balance sheet. I mean, there's already a couple highways that are pretty straight.
I don't know how unusual this situation is exactly, though.
Higher speed trains need much larger turn radius so existing RoW is not suitable. They’re running into the same issue trying to build high speed rail into the SF Bay Area.