Just to be pedantic, the dumb car tunnels (or Loop), are the weird thing elon "invented" to "solve" traffic and reduce competition for his cars for urban transport. This eventually became one tunnel in LA to get between elon's house and office, and the dumb taxi tunnel in Las Vegas.

The hyperloop, where elon "invented" the vacuum train, is a separate thing that exists to distract from CAHSR, and elon didn't want to work on himself because "he's too busy", and not because it's effectively just a scam and won't work, and most of the companies that started up to develop it have since gone bust.