And yet Musk has repeatedly overpromised and underdelivered on self-driving functionality for Tesla. He aims high and while Tesla has delivered spectacularly on the dream of a viable electric car, it's so far failed at the promise of a self-driving computerized chauffeur. But why would it? The two problem sets are wildly different, and there's no reason that success in one implies success for the other.

Likewise, SpaceX has done some amazing things so far for private launches and the promise of reusability. But that doesn't imply that they are going to be able to solve the challenges required to get people to Mars. That's a wildly different problem set.