Space launch is a mature industry with multiple companies. Anyone who thinks SpaceX can lower the launch costs by orders of magnitude is either far to credulous or just doesn't understand what it takes to launch a rocket.
Space travel is also far less mature than tunnel boring technology, I’d expect advances in space travel before tunnel boring because there’s low hanging fruit. Space travel used to be done only by nation-states, only in the last 25-30 years has private space travel been possible. Tunnel boring machines were invented 200 years ago and were useful about 150 years ago.