The punishingly long time needed to get environmental approvals and overcome other permitting obstacles ("see Silver Line extension to IAD, new Hudson River tunnels, etc.") is a real problem. Musk's pipe dream drawing some attention to that would be worthwhile, even if his discussion of punching 200+ miles of tunnels through some of America's most intensely-developed cities looks comically naive.

His scheme won't be worthwhile if it becomes another futuristic vision (see maglev) that persuades people to hold off on investing in the kind of intercity transportation that the rest of the world knows already works and is busy building: high-speed rail.