Pragmatic, sensible and workarounds exist for the problems
Not hard vacuum, well below the milliTorr range. So relatively easy to create and maintain.
Sidesteps eminent domain because he plans to site next to Interstate 5.
1 track is more equal to a freeway lane than a conventional rail track, with its associated security fences etc.
Putting it on stilts mitigates the earthquake issue in CA and allows re boost if it slows down.
Small town don't have to be cut out of the loop as you could install Y joints (admittedly at very shallow angles) to allow them to join the path.
The joker in the pack is the software. We're looking at something like the Denver baggage handling system with the baggage carriers moving at M0.9. Anyone remember how well that worked out?
TBH I think it's a very clever idea and sidesteps the need for a working "Subterrene" but that SW issue is a biggie.
Musk has said he's not really interested in anything that either helps fund his trip to Mars or helps build the tech needed to get him there. I think this could help with the funding. The really attractive part of this is that it's incremental costs are low (relative to rail) once you've built the tube.
For the duration of a short drive and the price of a bus ticket (I'm guessing) you get a long journey done in a very short period of time.
BTW I've also learned that "Kantrowitz's limit" is why why drop a soda can into the end of an empty food tin it slides like an air piston. Interesting.