Or the tunneling machines are for building habitats on Mars. Well, it's a fun hypothesis at least. Anything that could improve traffic in major cities gets my vote of approval regardless of what other applications it has.
I think your point is probably closer to the truth. Musk's desire to travel to mars seems to stem from the fact that it's a pretty awesome, adventurous thing to do, so it's one that doesn't fade on some whims. Whatever people say about Musk, he undoubtedly is pushing humanity in a better direction so maybe we should leave him to it.
