Obviously Elon likes publicity stunts like this, and the current prototype is very far off from something that can compete with traditional subways, but it's no

Obviously Elon likes publicity stunts like this, and the current prototype is very far off from something that can compete with traditional subways, but it's not obvious to me the idea of many "dumb" tunnels with many small to medium-sized autonomous vehicles is a bad idea. Subways are kind of like circuit switched networks (more raw capacity), this is more like a packet switched network (more flexibility/overall efficiency). And with cheap enough tunneling it becomes horizontally scalable.