One could also use tunnels to build subways and presumably Hyperloops. I wonder, though, about why big infrastructure projects so horrendously expensive, in America in particular. There are developers, planners, consultants, politicians, unions, contractors, sub contractors, sub-sub contractors, and they're all out for all they can get. There are lawyers every step of the way. Nobody communicates well. Small hang-ups at the wrong place send the entire operation grinding to a halt. Can this be fixed? Is a big dumb tunnel digging operation the point of entry for infrastructure construction disruption in America? That would be nice. We're good at moving the bits around. We suck at atoms.

Or is Musk setting himself up to be the next Robert Moses? Someone with the capability to move mountains, but not terribly discriminating about whether or not a given mountain should be moved. Musk doesn't talk like someone who's ever had a discussion with an Urban planner about the real reasons as to why our transportation problems are problems.