I think he's more likely referring to Elon Musk's predictions about Autopilot and Tesla. Elon Musk has been promising "full self-driving" capability for years now (by which I mean he has already missed his first public deadline by years). I also find The Boring Company to be a little overly ambitious, as well as many other public comments Musk has made over the years.
I don't think there are many people saying Elon Musk hasn't done some absolutely amazing things. But he's famous for being late to deliver on just about everything, and some of his comments about self-driving cars are considered truly pie-in-the-sky by experts.
