He went through Queen's Commerce with my nephew, so I feel I can comment. All of his successes have come from the 'Palo Alto' technique. That means, realize that some people are 10 times more productive than the bunch and pay them accordingly. No company east of there does that.
Now, for design and software, that works really well. But other things come against basic physics.
Mr. Musk must realize a productivity improvement by a factor of 10 if he doesn't want to be 'bored' with the whole thing. He can't get that with actually digging the tunnels. It costs so much to excavate a cubic meter of soil and that's that. In past 30 years, giant digging machines have improved things maybe a factor of two, but they always get stuck. We are now flatlining the economics.
While I'm writing this, I'm thinking he can get a factor of 10 in operating the tunnels, by using a giant packet routing system, but first you have to dig. And go through a zillion faults in LA. Good luck in getting the busgus to admit that they don't mean anything - their lives are on the line. :)