I think remote work and online shopping are developing perfectly well without Musk's help. And I think we need to increase the density of cities (at least, city centres and inner suburbs).

How do the sleds preclude developing public transport? Why wouldn't we see mini-vans pick people up from homes or community hubs and then use the tunnels to take an express route to the CBD? Or larger sleds that accommodate a bus or truck sized pod? If these HOV pods avoided a congestion charge, there would be an incentive to use them.

Obviously drivers and their cars will fill any space given to them, and cycling tunnels might be too expensive, but hopefully a change in traffic flow and parking availability would make room and safety for cycling above ground.

Imagine buses with good cycling storage so you could ride to the hub, board a bus, zip to the CBD, alight and ride the last few kilometres to your destination.

Entrenched interests will fight it for a time, but it wouldn't surprise me if these guys could make it happen.