Ten years ago, after complaining that traffic was ‘driving him nuts’, Musk’s Boring Company began building underground tunnels to ease congestion on the roads. Did he overpromise and underdeliver? It’s another blindingly bright day in Las Vegas but I’m 30ft underground and strapped in for a rocket ride to the future. Actually, it’s a Tesla ride to the future, and not a self-driving one. And it’s pretty slow – my driver tells me the speed limit down here is 30mph. It’s also pretty short: the jour